1- The real length of a pen is 10 cm. A student measured it as 9.9 cm. Find absolute and relative error?X= X0 X = 10-9.9= 0.1

Length of pen = (10 0.1) cm

2- The real length of class is 9.11 m. A student measured it as 9.13 m. find absolute and relative error?X= X0 X =9.11 9.13= 0.02

Length of class = (9.11 0.0022) m

3- Find absolute and relative error when measuring area A of a rectangle its length is (6 0.1) m and its width is (5 0.2) m.Area A= length x widthRelation used is multiplyxo = 5 x 6 = 30 m 2r1 = 0.1/6 = 0.017r2 = 0.2/5 = 0.04r total = r1+r2=0.017 +0.04 =0.057

= 1.7

4- If L = L 1 + L 2 find L where: L 1 = (5.2 , L 2=5.8

Two small balls of mass (7.3kg) each, are separated by a distance 0.5 m between their centres. Calculate the mutual attraction force between them,

15- An apple has fallen from a tree. Find its velocity when it reached the ground if it took 1 second to the ground. Then, find the average velocity of the apple during falling and the height from which it fell

16- In an experiment to determine the acceleration due to gravity using falling water drops, the distance between the tap and the plate base is 1m, If the time taken by 100 drops is 45 s find the acceleration due to gravity

17- A body of mass 2 kg at rest affected by force 16 N. find its velocity after 4 seconds and the covered distance

The diagram illustrates a ball hung by a thread swinging in a certain vertical plane. If the ball mass is (4kg) and (g = 9.8m/s2 ) find the greatest velocity of the ball duringoscillation, neglecting the air resistance.

5- An athlete has moved to West through a displacement of (50 m ), then moved back to East through a displacement of (30 m ). Calculate the distance covered and the displacement of the athlete.First:the covered distance: :s = 50 + 30= 80 mSecond:the displacement of the athelet:d = +50 - 30 = +20 m

6- Find the resultant of two forces; one of them (Fx = 4N ) acting in x dimension, while the other Fy = 3N acting in y dimension.

7- If the magnitudes of two vectorsAre A= 5 and B=10 respectively and the angle between them is 60, find the result of each of dot product and cross product

18- A motorcycle is launched at 15m/s in a direction at an angle 30 0 to the horizontal.A- What is maximum height reached by the motorcycle?B- Find the time of its flight.C- What is the horizontal range reached by the motorcycle Vix =Vi cos = 15 cos 30 =13 m/s

Viy = V i sin =15sin 30 = 7.5 m/s

19- A stone of mass 600 gm is attached to a string of length 10 cm rotating at velocity 3 m/s Calculate the centripetal force. What do you expect if the maximum tension force that the string can afford is 50N?

The string will cut and the body moves in the tangent direction

An insulated container of Aluminium has mass 20 g and contains water of mass 150 g at temperature 20 co . A metal piece is heated to 100 co then dropped in the container , the final temperature of mixture is 25 co. Find specific heat of the metal where specific heat of water and Aluminium are 4200 and 900 J/kg.k respectively.

8- A person drove a car in a straight line to cover 8.4 km in 0.12 h. Because the fuel had run out, he walkedthrough 2 km along the same straight line to reach the nearest gas station after 0.5 h. Calculate the average velocity of this journey

9- If the person in the previous example returned back to his car in0.6 h find the average velocity and speed during the whole journey

11- An aeroplane lands on the runway at velocity 162 km/h and decelerates uniformly at 0.5 m/s2Find the time it takes till stops.

A satellite rotates around the earth in almost circular path at a height of(940 km) away from the earth's surface. Calculate the orbital velocity, the time required by the satellite to make a complete revolution around the earth, knowing that(R = 6360 km, M = 6 10 kg, G = 6.67 x 10 -11 Nm/kg)

A satellite completes its revolution around the earth in (100 min) and the length of its path = 60000 km.Calculate its orbital velocity, and its height above the surface of the earth, knowing that ( R = 6360km) .

at 15 co

Neglect the vessel

Lost energy= gained energy

x is the final temperature,

12- Mohamed drove a car at uniform velocity (30 m/s). Suddenly, he saw a child crossing the street and he applied the brakes to decelerate the car uniformly at (9 m/s). If Mohameds reaction time to use the brakes is (0.5s), find theDisplacement of the car till it stopped.

The moon rotates arround the earth in a circular orbit whose radius is 3.85x 10 5 km.It makes a complete revolution through (27.3 days). Calculate the mass of the earthUniversal gravitation constant 6.67 10-11Solution:Periodic time:T = 27.3 24 60 60 = 2.36 106 s

Calculate the work done by this girl who is carrying a bucket of mass 300 g to move it through a displacement of 10 m in the horizontal direction. Then, calculate the work done by theboy to lift a bucket of the same mass 10 cm in the vertical direction.(g = 10 m/s)Solution:Work done by the girl:since the force F exerted by the girl is perpendicular to displacement, work done equals zero.Work done by the boy:F = mg = 0.3 x 10 = 3NW = F. d cos

Calculate the kinetic energy of a car of mass (2000kg) moving at speed (72) km/hV = 72 x 5/18 = 20 m/s

13- A box fell from a helicopter that was staying still at 78.4 m high above sea level. Find the velocity by which the box hit water giving that acceleration due to gravity 9.8 m/sneglecting the air resistance. Also,Find the time it took till splash

14- A stone fell from the roof of a building. If the stone passed by a person standing in a balcony 5m highabove the ground 4 s later (consider g = 10 m/s), find:A- The building height.B- The stone velocity when passed by the person.

A cart of mass 20 kg is pulled by a force of 50N. The line of action of the force makes an angle 60 0 to the direction of displacement Find the work done by the force to displace the cart through (4 m)

W=Fdcos = (50)(4)(cos 60)=100JA static object at (30 m) high above the ground has potential energy (1470 J). If this object falls neglecting the air resistance and consider g = 9.8 m/s find:-- the kinetic energy and potential energy of the object at high.(20 m)-- the object velocity just before hitting the ground.