1 ASSAFWAH PRIVATE SCHOOL

CHECK POINT PHYSICS PHYSICS STUDY MATERIAL & WORK SHEETS

E mail: m_govindaraj@yahoo.co.uk Prepared by M.Govindaraj

Unit 1.1 Measurements

1. The SI units and Symbols. Physical Quantity Units Symbols Length Mass

Time

Temperature

Electric current

Amount of substance

2. The unit of length is _________________ 10 mm = __________ cm 100 cm = __________ m 1000 m = ___________ km

1 micro meter = __________ m 1 nanometer =_________m

3. Multiples of Powers Prefix Symbol Multiples of power

Giga G 109

Mega M 106

Kilo K 103

-------

Milli m 10-3 x 103 x 10-3

Micro µ 10-6

Nano n 10-9

2 Pico p 10-12

4. Mass:- It is the measure of amount of matter in it. The Unit of mass in SI unit is Kilogram 1000 mg = 1 g

1000 g = 1 Kg The terms weight and mass are not same . The different kinds of balances used to measure mass are 1 . Beam balance 2. Lever balance 3. Digital top pan balance.

5. Time: • Time is a duration • The unit of time is second(s) • The time measuring devices rely on some kind of constantly repeating oscillations. In

digital clocks and watches the oscillations are produced by a tiny quartz crystal.

6. Area: • The area of a square is given by Area = length x length • The area of rectangle is given by Area = length x width • The area of circle is A = π r2

• Area of triangle is A = heightxbreath21

Length width length length Square Rectangle circle Height base base base Equilateral Triangle Right angle triangle Triangle

The SI unit of area is meter square(m2)

Conversion factors of area __________ mm2 = 1 cm2 1 mm2 = ________cm2

diameter

3 ___________ cm2 = 1 m2 1 cm2 = ________ m2 ____________ m2 = 1 km2 1 m2 = ________ km2

7. Volume: Volume is the amount of space occupied. The SI unit of volume = __________ For a regularly shaped object like a rectangular block the volume is given as Volume = length x breadth x height

= Area of cross section x height (or length) Volume of cube = length3 = l3

Volume of cuboid = length x width x heigth

Volume of cylinder = π r2 h

Volume of sphere = 3

34 rπ

Volume of semi-sphere = 3

32 rπ

Cube Cuboid Cylinder

Conversion factor of volume __________ mm3 = 1 cm3 1 mm3 = __________ cm3 __________ cm3 = 1 m3 1 cm3 = __________ m3

__________ m3 = 1 km3 1 m3 = __________ 1 km3

8. Density: The mass per unit volume of a substance is called Density.

Density = volumemass

SI unit of volume = kg /m3 , in CGS unit is g / cm3 Solids are often very dense and gases have very low densities.

4 Density measurements:

1. Regularly shaped solids. Find the mass by using a balance. Find the volume by measuring its dimensions using a ruler. Then using the formula mass/volume fine the density.

2. Irregularly shaped solid like pebble. Find the mass of the solid. Find the volume and then use formula (fig 72GCSEphy book)

3. To find the density of liquid Find the volume of the liquid Transfer the liquid into a beaker and weigh it to find the mass. Then use the formula to find the density

5

EXERCISES

1. A stopwatch is used to time a race. The diagrams show the watch at the start and at the end of the race. How long did the race take?

_____________ _________________ 2. Which of the following units is correct physical quantity. Circle the right one

Area cm2 metre cm3 Kelvin Volume cm metre m3 Mm Temperature Ampere kelvin cm cm2 Electric current metre cm3 Ampere m2 Distance Metre Kilogram Kelvin m2 Perimeter Kilogram kelvin Ampere Metre

3. Circle the write matching in the following

Mass Volume Density Area A Kelvin M2 Kg/m3 m2 B Kg cm3 g/cm3 m2 C g cm2 Kg/cm2 m3 D Ampere Kelvin g/m3 Kilometer

4. Write the reading in the scale

Reading ___________________ Reading ________________________

6 5. The diagrams show the times on a stop-clock at the beginning and at the end of an experiment.

How long did the experiment take?

____________ ______________

6. Find the volume of the water in the beaker

Volume _____________ Volume _____________ 7. Gap between the electrodes is ____________________________

8. A decorator wishes to calculate the area of a bathroom tile so that he can estimate the amount of adhesive(glue) that he needs to buy.

What must he use?

7 A a measuring cylinder only B a ruler only C a measuring cylinder and a clock only D a measuring cylinder and a ruler only

9. Find the mass of the copper sulphate in the pan

Mass of Copper Sulphate _______________ 10. The thermometers in Figures show the temperature of two different water. Record the

temperature

Reading ________________

Reading _________________ 11. Show the positions of the pointers of the ammeter reading 0.375 A, and the voltmeter reading 1.50

V. in the figures

12. The diagram shows the level of liquid in a measuring cylinder.

What is the volume of the liquid?

8 13. A floor is covered with square tiles. The diagram shows a ruler on the tiles. How long is one tile?

14. Fill in the blanks in the following. Density is mass per unit volume and measured in _________________ or __________________ .

15. The diagram shows a measuring cylinder. Which unit would be most suitable for its scale?

A mm2 B mm3 C m2 D m3

16. Write the reading on ammeters

-------------- -------------- -------------

9 17. A measuring cylinder is used to measure the volume of a liquid.

What is the volume of the liquid?

18. A glass tank contains some water. The length QR and the width RS of the tank are known. What other distance needs to be measured in order to be able to calculate the volume of the water?

19. A measuring cylinder contains some water. When a stone is put in the water, the level rises.

What is the volume of the stone? A 50 cm3 B 70 cm3 C 75 cm3 D 125 cm3

20. Figure shows a pile of 15 glass microscope slides, drawn actual size.

10 (a) (i) On Fig. 3.1, use your rule to measure h, the height in mm of the pile of slides.

h = ...........................

(ii) Calculate the thickness t of one slide. t = ............................ (iii) The surface area A of each slide is 1200mm2. Calculate the volume V of one slide using the equation V = A x t. V = ........................... (iv) The mass of one microscope slide is 3.7 g. Calculate the density d of the glass, in g/mm3, using the equation d = m/V. Give your answer to an appropriate number of significant figures. d = …………………….

21. In an experiment to find the density of some oil, a student takes the following readings.

Fig 1 Fig 2 Fig 3 Mass of empty jug = 610g Mass of jug with 500cm3 of oil = 1020g (a) (i) Calculate the mass of oil in the jug. mass of oil =........................ g (ii) Calculate the density of the oil. density of oil =........................ (iii) How could the volume of the oil be more accurately measured than with the measuring jug? ............................................................................................................................... (b) Water is denser than oil. On Fig. 3, mark approximately where the surface of the same mass of water would be if it replaced the oil.

22. A student is given the following apparatus in order to find the density of a piece of rock. Balance, measuring cylinder that is big enough for the piece of rock to fit inside cotton and water.

The rock has a mass of approximately 90 g. (b) Describe how the volume of the rock could be found.

11 ..................................................................................................................................... .................................................................................................................................... (c) The mass of the rock is 88 g and its volume is 24 cm3. Calculate the density of the rock. density of rock = ..............................

23. Cylindrical can is rolled along the ruler shown in the diagram.

24. A piece of cotton is measured between two points on a ruler. What is the distance once round the

pen?

25. (a)The string is wrapped 5 times round the beaker and marked as shown in Fig. 1

The string is held against a metre rule as shown in Fig.2.

Fig 1 Fig 2

(i) Write down the length of the string between the marks. length = ........................cm

12 (ii) Calculate the circumference c of the beaker. c = ........................cm (iii) Suggest one source of error in this method of determining the circumference. ................................................................................................................................ ................................................................................................................................. (iv) Suggest one improvement to this method. ................................................................................................................................. ................................................................................................................................. (b) A rule is placed beside the beaker, as shown in Figure.

(i) Write down the depth d of the water in the beaker. d = ...................... cm (ii) Calculate the surface area A of the curved surface of the beaker up to the water level using the equation A = dc. A = ............................

26. A shop-keeper places two identical blocks of cheese on a set of scales and notices that their

combined mass is 240 g. Each block measures 2.0 cm x 5.0 cm x 10.0 cm. What is the density of the cheese? A 0.42 g / cm3 B 0.83 g / cm3 C 1.2 g / cm3 D 2.4 g / cm3

27. The masses of a measuring cylinder before and after pouring some liquid into it are shown in the

diagram. What is the density of the liquid?

A 3/100120 cmg B 3/

100140 cmg C 3/

180120 cmg D 3/

180140 cmg

13

28. The diagram shows some liquid in a measuring cylinder. The mass of the liquid is 16 g.

What is the density of the liquid?

29. The same mass of four different liquids is placed in some measuring cylinders.

Which measuring cylinder contains the liquid with the greatest density?

30. Figure shows the top part of a measuring cylinder containing some liquid. (a) What is the volume of liquid in the measuring cylinder? volume = .............................cm3 (b) Figure indicates four ways the observer’s eye could look when taking the reading from the measuring cylinder. Put a circle around the eye position that gives the correct reading. (c) In order to fill the measuring cylinder up to the 100 cm3 mark, 80 drops of the liquid are added to the liquid already in the measuring cylinder.

14 Calculate the average volume of one drop. average volume of a drop = .......................cm3

31. A packaging company purchases corrugated cardboard boxes in which to pack its goods. The

boxes are not made up when they are delivered, but are flat, as shown in Fig. 1 (a) A bundle of these boxes measures 0.60m x 0.50 m x 0.20 m and has a mass of 7.2 kg. (i) Calculate the volume of the bundle of boxes. volume = .........................

Fig 1 Fig 2

(ii) Calculate the density of the corrugated cardboard. density = ............................... (b) Corrugated cardboard is made up of 3 sheets of thick paper stuck together. Fig. 2 shows an enlarged view of the edge of a sheet of corrugated cardboard. (i) Here is an incomplete sentence about the paper. The density of the paper is................................... that of the corrugated cardboard. Which of the words below correctly complete the sentence? Tick one box. greater than the same as less than (ii) Explain your answer to (b) (i). .................................................................................................................................. ..................................................................................................................................

32. In an experiment to determine the volume of glass beads, a student used two different methods.

The student used a displacement method to determine the volume of a glass bead. Fig. 1

15 and Fig. 2 show how this was done. (b) (i) Write down the values of the readings taken 1. ________ 2. __________ (ii) Calculate the volume of 225 glass beads. volume = ..............................

Fig 1 Fig 2 (iii) Calculate V, the average volume of one glass bead

V = .............................

(c) Suggest which of the two methods will give the more accurate result for the volume of a glass bead. Give a reason for your answer. ....................................................................................................................................... ........................................................................................................................................ ........................................................................................................................................

33. (a) An unopened bottle of olive oil has a mass of 0.97 kg. The empty bottle has a mass of 0.51 kg. Calculate the mass of the olive oil.

mass of olive oil = .................................. kg

The olive oil is poured into three 250 cm3 measuring cylinders. The first two cylinders are filled to the 250 cm3 mark. The third is shown in figure below.

16 (i) What is the volume of the olive oil in the third measuring cylinder? volume = ..................................cm3 (ii) Calculate the volume of the olive oil in the unopened bottle. volume = ..................................cm3 (iii) Calculate the density of the olive oil. Express your answer to 2 significant figures.

density = ...............................

34. The clock on a public building has a bell that strikes each hour so that people who cannot see the clock can know what hour of the day it is. At precisely 6 o’clock, the clock starts to strike. It strikes 6 times. At the first strike of the bell, a man’s wrist-watch is as shown in Fig. 1.

Fig 1 Fig 2

(a) When the bell strikes for the sixth time, the wrist-watch is as shown in fig 2 (a)Calculate the time interval between the 1st strike and the 6th strike. time interval = ……………… s (b) Calculate the time interval between one strike and the next. time interval = ………………s (c) At precisely 11 o’clock, the clock starts to strike. Calculate the time interval between the 1st strike and the 11th strike. time interval = ………………s

35. A measuring cylinder contains 100 cm3 of water. 20 cm3 of the water is poured into a beaker.

17

Fig 1 Fig 2 On Fig.1 mark the level of the water left in the cylinder. (b) A rule, calibrated in cm, is placed alongside the measuring cylinder, as shown in Fig. 2 (i) What is the length of the measuring cylinder, from zero up to the 100 cm3 mark? ................................................................................................................................. (ii) The volume of a cylinder is found using the equation volume = cross-sectional area x length. Calculate the cross-sectional area of the measuring cylinder. cross-sectional area = .................................

18 ASSAFWAH PRIVATE SCHOOL

AL KHOUD

MECHANICS STUDY MATERIALS & WORKSHEETS IGCSE PHYSICS –GRADE 9

DISTANCE AND DISPLACEMENT

1. Distance is the length of path traveled by the body. 2. Displacement is the shortest distance traveled by the body in a straight line.

Distance

A B Displacement

3. Unit of both distance and displacement is metre. 4. GRAPHICAL REPRESENTATION OF MOTION: The nature of motion of bodies can

be studied easily studied from its graphical representation. Time is plotted along X axis and distance is plotted along Y axis.

5. USES OF GRAPH: Distance time graph is used to determine the following 1. The position of the body at any instant of time. 2. Distance covered by a body during particular interval of time can be seen.

3. Motion of two moving bodies can be compared. 4. Velocity at any instant/duration 5. Average velocity 6. Instantaneous velocity

6. The gradient/slope of the distance time graph gives the velocity of the body.

Distance Time

19 Distance

Time Distance Time Distance Time

7. The following graph is the distance -time graph. Answer the questions below. Distance m/s

B

A C D E O

Time/s

i. Which segment(s)/points of the graph has a. constant speed

20 b. increasing speed

c. uniform acceleration

d. body stopped

e. coming back to same place

ii. What is the displacement of the body during its journey?

SPEED & VELOCITY

8. Speed is distance traveled by a body in unit time. It has no direction.

Speed = time

ceDis tan

Unit of speed is m/s.

9. Velocity is displacement of a body in unit time. It has direction.

Velocity = time

ntDisplaceme

Unit of displacement is m/s.

10. Velocity/speed is many type. is 1. increasing speed 2. Decreasing speed 3. Instantaneous speed 4. Average speed

11. Average Speed = timeTotal

cedisTotal tan

12. Relation between m/s and km/hour. 1 m/s = 185 km/h

5

18 m/s = 1 km/hr

ACCELERATION

13. Acceleration is rate of change of velocity. Or change in velocity in unit time.

Acceleration = t

UVtV

TimevelocityinChange −

=∆∆

=

14. If body travels with increasing speed the acceleration is positive. If body travels with uniform speed the acceleration is zero. If body travel with decreasing speed the acceleration is negative called negative

acceleration or retardation or deceleration.

15. If acceleration is zero the equation is time

ntdisplacemeVelocity = D

V x T

21 16. VELOCITY TIME GRAPH OR SPEED TIME GRAPH. It is a graph obtained by

plotting velocity of the body along Y axis and time along X axis. Velocity m/s

A B O C M N Time /s

EXERCISE

1. The graph shows how the speed of a car changes with time.

Which of the following gives the distance traveled in time interval OR? A the area OPQR B the length PQ C the length (QR – PO) D the ratio QR/PO

2. A stone falls freely from the top of a cliff into the sea. Air resistance may be ignored. Which graph shows how the acceleration of the stone varies with time as it falls?

Uniform acceleration

Uniform velocity/zero acceleration

Uniform deceleration

22 3. A child is standing on the platform of a station, watching the trains.

A train traveling at 30 m / s takes 3 s to pass the child.

What is the length of the train? A 10 m B 30 m C 90 m D 270 m

4. A tunnel has length 50 km. A car takes to travel 20 min to travel between two ends of the tunnel.

What is the average speed of the car? A 2.5 km/ h B 16.6 km/ h C 150 km/ h D 1000 km/ h

5. A snail crosses a garden path 30 cm wide at a speed of 0.2 cm/s.

How long does the snail take? A 0.0067 s B 6.0 s C 15 s D 150 s

6. The diagram shows a speed-time graph for a body moving with constant acceleration. What is represented by the shaded area under the graph?

A acceleration B distance C speed D time

7. A tunnel has a length of 50 km. A car takes 20 min to travel between the two ends of the tunnel. What is the average speed of the car?

A 2.5 km/ h B 16.6 km/ h C 150 km/ h D 1000 km/ h

8. Which statement about the mass of a falling object is correct?

A It decreases as the object falls. B It is equal to the weight of the object. C It is measured in newtons. D It stays the same as the object falls.

23 9. The three balls shown are dropped from a bench. Aluminium, Lead & wood Which balls have the same acceleration?

A aluminium and lead only B aluminium and wood only C lead and wood only D aluminium, lead and wood

10. The diagram shows the speed-time graph for an object moving at constant speed. What is the distance traveled by the object in the first 3 s?

A 1.5m B 2.0m C 3.0m D 6.0m

11. A car accelerates from traffic lights. The graph shows how the car’s speed changes with time. How far does the car travel before it reaches a steady speed?

A 10 m B 20 m C 100 m D 200 m

12. Which speed / time graph applies to an object at rest?

13. A small steel ball is dropped from a low balcony. Ignoring air resistance, which statement describes its motion?

A. It falls with constant acceleration. B. It falls with constant speed.

24 C. It falls with decreasing acceleration. D. It falls with decreasing speed.

14. The graph represents the movement of a body accelerating from rest.

After 5 seconds how far has the body moved?

A 2 m B 10 m C 25 m D 50 m 15. A man crosses a road 8.0 m wide at a speed of 2.0 m / s.

How long does the man take to cross the road?

A 4.0 s B 6.0 s C 10 s D 16 s 16. The graph represents part of the journey of a car.

What distance does the car travel during this part of the journey? A 150 m B 300 m C 600 m D 1200 m

17. A bus starts from Muscat at 2:30 and reaches Salalah by 14:10. The distance between Muscat and Salalah is 950km a. Find the total time taken to reach Salalah

25 b. Find the distance in meter, centimeter.

1. If a car travels 300km in 5 hours. Find the average speed in km/h, m/h, km/sec. 2. Saif takes 20 minutes to cover a distance of 3.2km on a bicycle. Calculate the velocity in units of km/min , m/min , km/h. 3. Ahmed is moving in his car with a velocity of 45km/h. How much distance will be cover in one minute.

4. The speed of a cyclist reduces uniformly from 2.5 m/s to 1.0 m/s in 12 s.

(a) Calculate the deceleration of the cyclist. deceleration = .................................. (b) Calculate the distance traveled by the cyclist in this time. distance = ..................................

26 FORCE & ACCELERATION

1. Force is push or pull. 2. Force changes the state of rest or uniform motion. 3. Force can change i. speed of body ii. direction of motion iii. shape and size of the body

4. The change of shape and size of the body can be temporary or permanent. 5. Unit of force is Newton. 6. A force of one Newton will make a mass of one kilogram accelerate at one metre per second squared. 7. Equation for force is F = m a 8. Force is a vector quantity. 9. CONTACT FORCE : It is the force exerted when two objects are in contact. 10. NON CONTACT FORCE : These forces can act over large distance with out two objects

touching. Examples : Gravitational forces, Magnetic forces. 11. Resultant Force : If more than one force acting on a body the effective force acting on the body is called resultant force.

A person is pushing a car. But if the push force is same as the force of friction, the two forces will cancel each other .So the car does not move. If one more person helps him to push the car the forward force is bigger. Both the forces pushing the car are in the same direction. If the force of push by each is 300 N Then, total forward force = 300 N + 300 N = 600 N If the force of friction is 400 N Then the resultant force = 600 N – 400 N = 200 N.

12. More than one force: If more than one force acting on a body in same direction, the resultant force is sum of the forces.

13. If more than one force acting on a body in opposite direction, the resultant force is the difference between the forces and it acts along greater direction.

What is the resultant? What is the resultant ? 14. Two horizontal strings are attached to a soft rubber ball.

A force of 10 N pulls on one string.

1. The ball does not move. What is the value of the force on the other string

Body 20N 30N 30N 50N

27 2. What change to the rubber ball do the two forces cause?

15. Find the resultant of force 5N and a force of 12 N acting at the same point on an object if the forces act in

a. the same direction in the straight line.

b. opposite direction in the same line

16. Force of 20N acting due east and 40N due west. What is the resultant force acting and its

direction? 17. 30N, 15N, 20N & 15N Forces are acting due east, north, west and south. Find the direction and

magnitude of resultant force. Draw force diagram 18. 25N, 30N 45N & 30N are acting along east, north, west and south. Find the direction and

magnitude of resultant force. Draw force diagram. 19. 20N and 30N are acting along x- and y – axis. Draw scale diagram and connect the origin to

diagonally opposite edge find the length of diagonal. Take 5N as 1cm as scale.

28 20. 40N and 50N are acting at angle of 450 on the body. Draw scale diagram ( as in previous

question) and find the resultant of the forces. 21. Find the resultant force due to two forces 7N & 10N acting at 300 between the forces using scale

diagram.

22. Six trolleys are acted by different forces. Answer the following questions.

a. What is the resultant force and its direction acting on each these trolleys?

MASS & WEIGHT

MASS WEIGHT

1. It is the measure of the amount 1. It is the pull of the earth on the of matter in an object object

2. It is measured in kilogram 2. It is measured in Newton

3. It is constant every where 3. It is different in different place

4. It is a scalar quantity 4. It is vector quantity. 5. It is measured by beam balance 5. It is measured by spring balance.

23. The relation between weight and mass is 24. The weight of a body in moon is 1/6 of that on the earth.( i e 1.67 m/s2

A

D

B C 5N

57N 20 60N

50N 15N 25N 15N 5N

5N 92N 92N E F

W = mass x gravity = m g

29 25. The largest value of gravity on the earth is 9.81 m/s2 at poles and lowest value is 9.78 m/s2 at

equator. 26. Find the mass and weight of the body given in table

Weight/N Mass/kg Gravity m/s2 Predict earth/moon 20 10 35.6 9.8 90000 9.8 85 ton 10 570 57 51.86 29.3 56.78 34 204 10 690 1.67 0.12 9.8

27. Name the forces that

a. Causes objects to fall towards the earth.

b. Makes marble rolled across level ground eventually come to rest.

28. Assuming g = 10N/kg on earth and 1.7N/kg on the moon. Find the weight of a. A girl of mass 40 kg

1. mass of the girl in moon? 2. weight in moon?

b. Pin of mass 300 mg c. mass of pin in moon?

29. The mass of a man in moon is 55 kg, what is his

a. mass in the earth

b. mass in the space

c. mass in the sun

d. weight in the earth (g = 10 m/s2 )

30 e. Weight in the moon (g = 0.167 m/s2)

f. Weight in the space ( g = 0 )

30. A body weighs 50 N in the earth is weighted in another planets. If its weight is 32 N in the planet,

find the acceleration due to gravity in the planet.

EXERCISE

1. In which of these situations is no resultant force needed? A a car changing direction B a car moving in a straight line at a steady speed C a car slowing down D a car speeding up

2. Below are four statements about the effects of forces on objects. Three of the statements are correct. Which statement is incorrect? A. A force can change the length of an object. B A force can change the mass of an object. C A force can change the shape of an object. D A force can change the speed of an object.

3. Which of the following statements is correct? A Mass and weight are different names for the same thing. B The mass of an object is different if the object is taken to the Moon. C The weight of a car is one of the forces acting on the car. D The weight of a chocolate bar is measured in kilograms.

4. Which statement is correct? A Mass is a force, measured in kilograms. B Mass is a force, measured in newtons. C Weight is a force, measured in kilograms. D Weight is a force, measured in newtons.

5. Below are four statements about the effects of forces on objects. Three of the statements are correct. Which statement is incorrect?

A A force can change the length of an object. B A force can change the mass of an object. C A force can change the shape of an object. D A force can change the speed of an object.

6. In which of these situations is no resultant force needed?

A a car changing direction B a car moving in a straight line at a steady speed C a car slowing down D a car speeding up

7. Two forces act on an object. In which situation is it impossible for the object to be in equilibrium?

A The two forces act in the same direction. B The two forces act through the same point.

31 C The two forces are of the same type. D The two forces are the same size.

8. What is the gravitational force that the Earth exerts on an object? A the density of the object B the mass of the object C the volume of the object D the weight of the object

9. What are the correct unit of mass and weight?

Mass Weight A Kg Kg B Kg N C N Kg D N N

10. A girl and a boy are pulling in opposite directions on a rope. The forces acting on the rope are

shown in the diagram. Which single force has the same effect as the two forces shown? A 50 N acting towards the girl B 350 N acting towards the girl C 50 N acting towards the boy D 350 N acting towards the boy

11. Which statement about the mass of a falling object is correct?

A It decreases as the object falls. B It is equal to the weight of the object. C It is measured in newtons. D It stays the same as the object falls.

12. Which statement is correct? A The mass of a bottle of water at the North Pole is different from its mass at the Equator. B The mass of a bottle of water is measured in newtons. C The weight of a bottle of water and its mass are the same thing. D The weight of a bottle of water is one of the forces acting on it.

13. The weights of four objects, 1 to 4, are compared using a balance. Which object is the lightest?

A object 1 B object 2 C object 3 D object 4

32 14. Three horizontal forces act on a car that is moving along a straight, level road air resistance

friction driving force. Which combination of forces would result in the car moving at constant speed?

33 ASSAFWAH PRIVATE SCHOOL

AL KHOUD IGCSE PHYSICS – GRADE – 9

1. We see, feel and hear lot of waves in our daily life. Eg sound, light, waves on water surface, wave

in musical instruments, oscillation of air in wind pipes, simple pendulum etc, 2. The waves motions are due to vibration, oscillation, rotation etc.

3. Vibration: A regular to and fro(back ward) motion of a body about mean position. 4. Oscillation: A complete to and fro motion about its mean position. Eg Simple pendulum 5. Wave : The propagation of disturbances from one particle to another in forward direction in a

medium. 6. Vibrating body is the sources of waves.

7. Circular rings formed on water surface are called ripples. 8. Simple Pendulum: A metal bob connected with a light thread, the other end fixed to a hinge 9. One Oscillation of pendulum : Involves both a forward and backwards swing of the pendulum.

Direction of propagation Direction of vibration

Distance

Amplitude

One Wavelength λ

Half Wavelength λ/2

Oscillation of pendulum Vibration of blade

34 Definitions

10. Displacement : The displacement of a vibrating object is its distance from the rest or central position in either direction. The unit is metre.

11. Amplitude(a) The amplitude is the maximum displacement from the rest or central position in either direction. The unit is metre.

12. Period(T) The period is the time of vibrating object takes to makes one complete oscillation. The unit is second.

13. Wave length λ: The distance travelled by wave for one full vibration/ oscillation. Or The distance between two successive particles which are at exactly the same point in their paths at the same time and are moving in the same direction. Its unit is metre.

14. Frequency(f): The number of complete oscillations(or vibration/ cycles/rotation/ ) in one second. The unit is second-1 or cycles or Hertz(Hz).

15. Pitch

16. The relation between frequency and time period Frequency =

Pitch determines the frequency of the waves. Pitch determines the shrillness of the sound

Timeperiod1 f =

T1

17. Properties of wave 1. It carries energy 2. the medium doesn’t travel with the wave 3. The particle displace by wave motion vibrate about rest position. 4. Each particle vibrates in the same way, but the vibration have a time lag in the direction of travel of the wave. 5. The speed of a wave is not affected by the shape but affected by the nature of the medium it travels.

18. PROPERTIES OF SOUND 1. Sound is a form of energy. 2. Sound is longitudinal waves. 3. Sound requires medium for motion. 4. Sound doesn’t travel in vacuum 5. Sound travels through solid liquid and gas. 6. Sound wave can be reflected refracted, diffracted, interfered and polarized. 7. Velocity of sound in air is 330m/s. 8. Frequency : Frequency or pitch does not affect the speed. 9. Amplitude : Amplitude doesn’t affect the speed. 10. Frequency and pitch :Pitch depends on frequency. More the frequency more pitch. 11. Amplitude and Loudness : Loudness depends on amplitude. More the amplitude more the

loudness. 12. Amplitude and Intensity : The intensity is directly proportional to the square of wave amplitude.

I α a2 13. The intensity of sound wave is the rate at which it carries energy away from the source. Through

a unit area at right angles to the travel of the wave. 14. Echo : The reflected sound is called an echo. 15. Sound travels faster in solids, slow in liquids and slower in gas. 16. A distance train can be heard through railway track rather than hearing its sound through air. 17. A bomb is exploded under water, name what type of wave is passed out 1. from the bottom to water surface 2. water surface to near by area. 18. Sound of frequency 1-20Hz cannot be heard by human hear, called infrasonic sound. This range

of sound is called inaudible range.

35 19. The sound of frequency between 20Hz to 20000Hz is called audible sound, This sound can be

heard by human hear. 20. The sound of frequency more than 20000Hz(20KHz) called Ultra-sonic sound. 21.

Application of Ultrasonic sound

1. Bats use the ultrasonic waves to find direction of flight. 2. SONAR : The pulse echo technique used to find the depth of sea and presence of submarine in

the sea. The instrument used to produce the ultrasonic sound is called Fathometer. 3. In hospital it is used to find image of moving heart, and baby in the mother’s womb. 4. Ultrasonic spectacles used for blind person to estimate the distance away of something in front

of him.

S. NO

Wavelength Wave velocity Frequency Period

A. 20m/s

0.3 μ s

B. 4500 mm 300m/s

C. 200cm

350Hz

D. 350m/s

300Hz

E. 420m/s 0.022MHz

F. 2m 15Hz

400mm 5 s

2.5km 60min

5km 120min

2mm/s 2ms

5cm/s 500

0.036km/hr

36 Which of the above is a. Light waves _______________________ b. Sound waves _______________________ c. Ultrasonic waves _______________________ d. Infrasonic _______________________ e. Infra red rays _______________________

19. Find the wavelength and frequency of a wave whose time period is 0.4 micro seconds and velocity is 300000 km/s.

20. Find the frequency of a wave if its wave speed is 3000km/s and wavelength is 200cm. 21. From the given figures, find displacement, velocity wave length if frequency is 450Hz.

(m) A 3 2 1 0.04mm wavelength Displacement _________________________ velocity _________________ Wavelength___________________________

4 B 2 0 4micrometre Wavelength Displacement _________________________ velocity _________________ Wavelength___________________________ cm C 10 5 0 7mm Wavelength Displacement _________________________ velocity _________________ Wavelength__________________________

37 6

D

4 2 0 13/4cm Wavelength Displacement _________________________ velocity _________________ Wavelength___________________________

22. Find the Wavelength, displacement and frequency of the wave in the figures below if the velocity is 4m/s. UA Wavelength ___________________________ Displacement____________________ Freqency _____________________________ UB 4 2 0 3 μsecond Time Wavelength__________________________ Displacement_____________________ Frequency __________________________

38

Fill in the blanks

1. A complete to and fro motion of called

oscillation.

2. Wave

is propagation of disturbances in the medium.

3. A wave requires medium

to travel.

4. Simple pendulum

is a metal bob connected with a light thread, the other end fixed to a hinge.

5. One forward and backward swing of the pendulum in one oscillation

.

6. Distance traveled for one oscillation is called wavelength.

7. The amplitude

is the maximum displacement from the rest or central position in either direction.

8. The distance travelled by wave for one full vibration/ oscillation is called wavelength

.

9. Wave length

is the distance between two successive particles which are at exactly the same point in their paths at the same time and are moving in the same direction.

10. The unit of wavelength is metre

.

11. The unit of time period

is second.

12. The period is the time for one oscillation

.

13. Number of vibration in one second is frequency

.

14. Wave carries energy

in the medium

15. Hertz

is the unit of frequency.

16. Wave speed

is the distance traveled in one second.

17. Wave speed

= wave length x frequency

18. Wave speed =

Wave length

Time period

19. The unit of wave speed is metre/ second

.

20. The speed of a wave is independent

of the shape or amplitude.

21. The wave speed is independent of its .

frequency or wavelength

39 EXERCISE

1. The drawing shows a wave. Which labelled distance is a. the wavelength? b. the amplitude?

2. A student measures how far a cork moves up and down on a wave in a tank of water. Which quantity can he obtain from his measurement? A amplitude B frequency C speed D wavelength

3. A sound wave passes through the air, in the direction shown.

direction of travel of sound wave.

How does a particle of air move as the sound wave passes?

4. A woman tunes her radio to a station broadcasting on 200m.

What does the 200 m tell her about the radio wave? A its amplitude B its frequency C its speed D its wavelength

5. Which of these waves is longitudinal? A light waves B sound waves C water waves D X-ray waves

6. What is the approximate range of audible frequencies for most humans?

A 10 Hz to 10 000 Hz B 20 Hz to 20 000 Hz C 10 kHz to 10 000 kHz D 20 kHz to 20 000 kHz

40 7. 100 metre race is started by firing a gun. The gun makes a bang and a puff of smoke comes out

of the gun as shown. When does the finishing judge see the smoke and hear the bang?

8. A girl stands in front of a rock face. The girl claps her hands once. The speed of sound in air is 330m/ s. How long is it before she hears the echo?

A

3306602Χ s B

330660 s C

660330 s D

6602330×

s

9. A boy is stranded on an island 500m from the shore. He shouts for help, but all he can hear in reply is the echo of his shout from some cliffs. Sound travels at 340m/ s through the air. What is the time interval between the boy shouting and hearing the echo?

41

A

340500 s B

3405002× s C

500340 s D

5003402× s

10. The diagrams show four sources of waves. Which source generates longitudinal waves?

11. Two astronauts without radios can only communicate in space if their helmets are touching. There

is no air in space. What does this show about sound?

12. Waves are sent along two long springs X and Y as shown.

How should the wave motions in X and Y be described?

42

13. The waves reach the house because the hill has caused them to be A diffracted B radiated C reflected D refracted.

14. Which of the following can be heard by the human ear? A A whistle emitting a wave of frequency 50 kHz. B A bat emitting a wave of frequency of 30 kHz. C An insect emitting a wave of 300 Hz. D A vibrating spring emitting a wave of frequency of 5 Hz.

15. Boy A throws a large stone into a large still pond, as illustrated in Fig.

(a) Girl B hears the ‘plop’ sound of the stone entering the water a very short time after she sees the splash, but it is many seconds before the water wave reaches the edge of the pond where she is sitting.

43 Use this information to decide which wave travels fastest and which travels slowest. Write ‘fastest’ in one box and ‘slowest’ in another box. Leave one box empty. sound wave light wave water wave

16. A girl is walking along a path 1600m from the rock-face of a quarry (a place where stone is obtained).

(a) The quarry workers set off an explosion at X to break up some rock. The girl measures the time interval between seeing the flash and hearing the bang. The time is 5.0 s. (i) Calculate the speed of the sound. speed of sound = ………….………..m/s (ii) State what assumption you have made in your working in (i). .....................................................................................................................................................

17. A student wrote the following report about an experiment to measure the speed of sound in air.

My friend and I went into a field a long way from any buildings and measured the distance across the field. My friend stood at one side of the field and I stood at the other. My friend banged two pieces of wood together, and as I saw him do this, I started a stopwatch. I stopped the stopwatch when I heard the sound. We obtained the following readings. distance across field = 238m time for sound to cross field = 0.7 s

(a) Why was it necessary to be a long way from any buildings? ........................................................................................................................................................ (b) Why was it necessary to use such a large distance? ........................................................................................................................................................ (c) Suggest what the students could have used to measure the distance across the field. ........................................................................................................................................................ (d) Why was there a delay between the student seeing the pieces of wood come together

44 and hearing the bang? ........................................................................................................................................................ ........................................................................................................................................................ (e) Use the readings to calculate the speed of sound. speed of sound = ........................... (f) Suggest why it might have been a good idea for the students to repeat the experiment after they had exchanged positions. ........................................................................................................................................................ ........................................................................................................................................................

(g) A sound wave travels through air at a speed of 340 m/s. Calculate the frequency of a sound wave of wavelength 1.3 m. frequency = .........................

18. The speed of sound in air is 332 m/s. A man stands 249m from a large flat wall, as shown in Fig.

9.1, and claps his hands once. (a) Calculate the interval between the time when the man claps his hands and the time when he hears the echo from the wall.

time interval = .......................... s (b) A woman is standing 249m further away from the wall than the man. She hears the clap twice, once directly and once after reflection from the wall. How long after the man claps does she hear these two sounds? Tick two boxes. 0.75 s 1.50 s 2.25 s 3.00 s

19. (a) Fig.1 shows a machine for making loud sounds. It is called a siren. This consists of a rotating disc with 25 holes. As each hole passes the jet, a puff of air passes through the hole.

Fig 1

45 (i) How many puffs of air will there be during one revolution of the disc?

number of puffs = .................... (ii) The disc rotates 40 times per second. Show that the frequency of the note produced by the siren is 1000 Hz.

Fig 2 (b) The siren described in (a) is located some distance from a large building, as shown in Fig 2 The siren is briefly sounded once. A short time later, the sound is heard again. (i) Why is this second sound heard? .................................................................................................................................. (ii) What is the frequency of this second sound? Tick one box. less than 1000 Hz 1000 Hz more than 1000 Hz (iii) What is the amplitude of this second sound? Tick one box. less than the original sound the same as the original sound more than the original sound

20. The speed of sound in air is 340 m/s.

(a) Complete the table to show how far a sound wave has travelled 2, 3, 4 and 5 seconds after the sound was made.

Fig. 7 (b) On Fig. 1, draw the graph of distance travelled against time for the sound wave.

46

Fig 1 (c) A ship is sinking in the dark as shown in Fig. 2

Fig 2 The sailors on the ship fire a distress flare into the air. It explodes with a bang and a bright flash of light. (i) A lifeboat crew hear the bang and see the flash, but not at the same time. State which reaches the lifeboat first, the bang or the flash, and give a reason. .................................................................................................................................. .................................................................................................................................. .................................................................................................................................. (ii) The time interval in (c)(i) is 4.2 s. Use your graph in (b) to find how far away the lifeboat is from the flare. Show clearly on your graph how you got your answer. distance of lifeboat = ..................................m

47 ASSAFWAH PRIVATE SCHOOLS

IGCSE NOTES- PHYSICS LIGHT

1. Light is a form of energy. 2. Light is a wave motion, rather like the water waves you see on a pond. 3. Light travels at a very high speed – about million time faster than the speed of sound. 4. Speed of light is 300 million metres per second or 3 x 108 m/s.

Ray of light 5. Light travels in a straight line, called rectilinear. 6. Light is represented by a line with arrow, called ray of light. 7. If all rays are parallel they are called parallel rays. 8. If all rays are converging to a point, they are called converging rays 9. If all rays are diverging to a point, they are called diverging rays.

10. Object that produces their own visible light is called luminous sources – ex the Sun, other

stars, lamps, televisions etc. 11. Objects that are illuminated by light from other sources and reflected it into our eyes, called non

luminous objects – ex the moon, paper, walls, stone and most of objects. 12. Transparent Object. The objects in which light passes through it is called transparent object.

Ex – Glass, pure water etc. 13. Opaque Object: The object in which light can not pass through is called Opaque object. Ex –

Wood, card board, stone, wall, metal, etc. 14. Translucent Object : The object in which light passes partially is called translucent object Ex –

water, paper, sun glass etc. 15. Shadow : Shadows are formed when some rays of light continue to travel in straight lines,

which other rays are stopped by an object. 16. Eclipse is good example for shadow. 17. We can see an object only if light from it enters our eyes. 18. REFLECTION OF LIGHT: 19. The process of returning light back to same medium is called reflection. 20. The reflection is two types 1. Regular reflection 2. Irregular reflection(diffused reflection)

21. The regular reflection reflects parallel rays of light as parallel rays, while irregular reflection

reflects parallel light rays into different directions, as shown in figure.

Parallel rays Converging

Diverging rays

Regular Reflection Irregular Reflection

48 22. Regular reflection is from regular smooth surface, while irregular reflection is from irregular

surface. 23. The ray which incident on a surface is called incident ray. 24. The ray which reflected from a medium is called reflected ray. An imaginary line drawn

perpendicular to the mirror at the point where the incident ray strikes it is called the normal. 25. The angle of incidence is the angle between incident ray and normal. 26. Similarly angle of reflection is angle between reflected ray and normal.

27. The thing which placed in front of a mirror is called Object. 28. The thing which is seen/formed in the mirror is called Image. 29. Types of Images : The images are two types a) real image & b) virtual image. 30. Real image is the one which can be focused on a screen. Ex Cinema image. 31. Virtual image is the one which can not be focused on the screen. Ex Image seen in plane

mirror. 32. Reflection does not changes speed & wavelength of the light. 33. The image from a plane mirror can not be focused on a screen. 34. LAWS OF REFLECTION:

1. The angle of incidence equals the angle of reflection. i = r 2. The incident ray, the reflected ray and the normal all lie in the same plane. 35. Nature of Image formed by plane mirror.

a. Size of image formed by mirror is same as object. b. Virtual image c. Erect image d. Laterally inverted e. Distance of image from the mirror is same as that of object.

36. If we place an object 30cm away in front of a mirror, then the image formed is 30cm behind the mirror. The figure above shows how the reflected rays appear to come from the image. Thus the line joining the object to the image is at right angles to the mirror. The image in the plane mirror is laterally inverted.

37. Complete the ray diagram and locate the position of image

O O

Incidence ray Reflected ray

Angle of Reflection Angle of incidence

Mirror

Normal

i r

49 38. Periscope : Periscope is an optical instrument used in submarines & tanks so that people

below the surface can see what is happening above the surface.

39. REFRACTION OF LIGHT: Refraction of is the process of light travel from one medium into

other with change of its properties. 40. Although light travels in straight lines in one transparent material, such as in air, if it passes into

a different material, such as water, it changes direction at the boundary between the two. The bending of light when it passes from one medium to other is called REFRACTION.

A. A ray of light is bent towards the normal when it enters from less denser medium into an

optically denser medium at an angle (from air to glass) B. A ray is bent away from the normal when it enters an optically less dense medium(from

glass to air) C. A ray emerging from a parallel sided block is parallel to the ray entering , but is displaced

sideways D. A ray traveling along the normal is not refracted.

41. Speed & wavelength of light are less in air than that in water/glass. 42. Glittering of diamond is because of high refractive index. The light under goes multiple

reflection inside the diamond.

Angle of refraction r

i

i

glass

air

Mirror

50 EXERCISES

1. The angle between an incident ray and the mirror is 300. W

a. What is the angle of incidence? b. What is the angle of reflection? c. What is the total angle turned by the ray?

2. A boy with a mouth 5cm wide stands 2m from a plane mirror. Where is his image and how wide is the image of his mouth? He walks towards the mirror at 1m/s. At what speed does his image approach him?

3. Find the known angles

Name the following

4. Copy and complete the diagram

42

51 5. From the picture answer the following question

a. At what distance he can see his image ? ________________________ b.Can he see his foot ________________________

c. If he is 150 cm tall, what minimum height of mirror is required to see he image he wants to see his foot what distance he has to move from the mirror?

20cm Mirror

EXERCISES

1. Which diagram correctly shows a ray of light passing through a rectangular glass block?

2. The image of a clock face as seen in a plane mirror is shown.

What is the actual time on the clock? A 1.25 B 1.35 C 10.25 D 10.35

52 3. The diagram shows the image of a clock in a plane mirror. What time is shown?

A 02:25 B 02:35 C 09:25 D 09:35

4. A ray of light passes through a window. Which path does it take?

5. A student looks at the letter P on a piece of paper, and at its reflection in a mirror.

What does he see?

6. The diagram shows the image of a clock face in a plane mirror.

Which of these times is shown? A 02.25 B 02.35 C 09.25 D 09.35

7. (a) A man looks at his reflection in a vertical mirror. This is shown from the side in Fig. 1 (i) On Fig.1, accurately mark with a clear dot labelled B where the image of the tip A of

53 the man’s beard will be. (ii) On Fig.1, accurately draw a ray from the tip of the man’s beard that reflects from the mirror and goes into his eye. You may use faint construction lines if you wish. Use arrows to show the direction of the ray. (iii) The man can see the image, but it cannot be formed on a screen. What name is given to this type of image? ..................................................................................................................................

Fig 1 Fig 2 Reflection seen in the mirror

(iv) Write down the equation that links the angles of incidence and reflection that the ray makes with the mirror. (b) A girl looks into a bathroom mirror to brush her hair. Fig.2 shows what she sees in the mirror. (i) In which hand is she holding the brush? Tick one box.

left hand □ right hand □

(ii) She has a spot on her skin just below her left eye. Mark clearly on Fig. 12.2 where this will appear on the reflection.

8. (c) The light in the optical fibre has a wavelength of 3.2 x 10–7 m and is travelling at a speed of

1.9 x 108m/s. (i) Calculate the frequency of the light.

frequency = …………………... (ii) The speed of light in air is 3.0 x 108m/s. Calculate the refractive index of the material from which the fibre is made.

refractive index = …………………...

54 9. In this question, drawing should be done carefully. Fig. shows a ray of light striking mirror 1

at point X.

(a) On Fig, (i) draw the normal at X, (ii) draw the ray reflected from mirror 1, (iii) mark the angle of incidence using the letter i and the angle of reflection using the letter r.

(b) Mirror 2 is parallel to mirror 1. The reflected ray from mirror 1 strikes mirror 2. Compare the direction of the ray reflected from mirror 2 with the incident ray at X. You may do a further construction if you wish. Complete the sentence below. The reflected ray from mirror 2 is ..................................................................................... ..........................................................................................................................................

10. (a) Fig. 7.1 shows two rays of light from a point O on an object. These rays are incident on a

plane mirror.

Fig. 1

(i) On Fig.1, continue the paths of the two rays after they reach the mirror. Hence locate the image of the object O. Label the image I. (ii) Describe the nature of the image I. ............................................................................................................................................ ............................................................................................................................................

11. Fig. shows a ray of light OPQ passing through a semi-circular glass block.

(a) Explain why there is no change in the direction of the ray at P. ..................................................................................................................................................... ..................................................................................................................................................... (b) State the changes, if any, that occur to the speed, wavelength and frequency of the light as it enters the glass block.

55 ...................................................................................................................................................... ...................................................................................................................................................... .....................................................................................................................................................

12. An inventor is trying to make a device to enable him to see objects behind him. He cuts a square box in half diagonally and sticks two plane mirrors on the inside of the box. A side view of the arrangement is shown in Fig. 1

Fig 1 Fig 2

Fig. 2 shows the arrangement, drawn larger. Fig. 2 shows parallel rays from two different points on a distant object behind the man. (a) Carefully continue the two rays until they reach the place where the inventor’s head will be. (b) Look at what has happened to the two rays. What can be said about the image the inventor sees? ..........................................................................................................................................................

13. A student investigates the refraction of light through a transparent block. He place the transparent block on a sheet of plain paper, largest face down, and draws a line round the block. He draws a line to represent an incident ray and places two pins W and X in the line. Fig. 5.1 shows the outline of the block and the incident ray.

56 (a) On Fig. 5.1, draw a normal to line AB at the point where the incident ray meets the block. The incident ray is drawn on the diagram. The positions of the two pins W and X that mark the incident ray are shown. (b) Measure the angle of incidence i i = ……………..

(c) Draw in the refracted ray with an angle of refraction of 20°. Continue this line until it meets the line CD. (d) The ray emerges from the block in a direction that is parallel to the incident ray. Draw in this emergent ray. (e) Two pins Y and Z are placed so that the pins W and X, viewed through the block, and the pins Y and Z all appear exactly in line with each other. Mark on the diagram, with the letters Y and Z, where you would place these two pins.