Edexcel ScienceiGCSE Physics

F. Motion in the Universe2019-2020

Name:________________Physics Teacher:______________

House CG

Year 9

Specification Checklist

1.04 know and use the relationship between average speed, distance moved and time taken:

average speed=distance travelledtime taken

s=dt

1.18 know and use the relationship between weight, mass and gravitational field strength:

weight = mass × gravitational field strength

W = m × g

8.01 use the following units: kilogram (kg), metre (m), metre/second (m/s), metre/second2 (m/s2), newton (N), second (s), newton/kilogram (N/kg)

8.02 know that:• the universe is a large collection of billions of galaxies• a galaxy is a large collection of billions of stars• our solar system is in the Milky Way galaxy

8.03 understand why gravitational field strength, g, varies and know that it is different on other planets and the Moon from that on the Earth

8.04 explain that gravitational force:• causes moons to orbit planets• causes the planets to orbit the Sun• causes artificial satellites to orbit the Earth• causes comets to orbit the Sun

8.05 describe the differences in the orbits of comets, moons and planets

8.06 use the relationship between orbital speed, orbital radius and time period:

orbital speed=2×π×orbitalradiustime period

v=2×π ×rT

Motion in the Universe – Science (Physics) 2

Key Words

Key Word Image Definition

Comet A celestial object consisting of a nucleus of ice and dust and, when near the sun, a ‘tail’ of gas and dust particles pointing away from the sun

Elliptical An oval shaped orbit.

Galaxy A collection of millions or billions of stars

Gravitational Field Strength

The strength of gravity on a planet or moon

Gravitational Force

The attraction force between two objects due to their masses

Milky Way Our galaxy.

Moon A ball of rock that orbits a planet.

Orbit The regularly repeated elliptical course of a celestial object or spacecraft about a star or planet

Orbital Speed The speed at which an object orbits a planet or star

Satellite An artificial or natural body placed in orbit round the earth or another planet in order to collect information or for communication.

Solar System The collection of eight planets and their moons in orbit round the Sun

Star A star is a celestial body that consists of a luminous sphere of plasma held together by its own gravitational field.

Time Period The time for one complete orbit

Universe A collection of billions of galaxies.

Motion in the Universe – Science (Physics) 3

Motion in the Universe – Science (Physics) 4

“Not only

is the Unive

rse stranger than we

think, it is

1: The Make-Up of the Universe and Orbital Shapes

Learning Outcomes:

1. Define the terms: Universe, Galaxy, Star and Solar System2. Describe how the Universe has evolved

3. Understand that the gravitational field strength “g” is variable on different moons/planets and can be calculated using the formula:

weight=mass×g

What do you already know?Add to the mind map below to brain dump everything you already know about the Universe.

Motion in the Universe – Science (Physics) 5

The Universe

“Not only

is the Unive

rse stranger than we

think, it is

The Universe, Galaxies, Stars and Solar Systems

Use your laptops and/or resources provides to research the following term.

See if you can find definitions (page 3) as well as some examples and interesting facts! Use labelled diagrams to help explain your findings.

Universe Galaxy

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Stars Solar System

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Motion in the Universe – Science (Physics) 6

The Evolution of the Universe

Key Ideas

1. Scientists believe the universe started with the Big Bang.2. During the first picosecond (10−12seconds) of cosmic time it is thought that the

currently understood laws of physics may not have applied. It also saw the emergence in stages of the four known fundamental forces.

3. The early universe, lasting around 377,000 years saw the various kinds of subatomic particles are formed in stages.

4. Next came the dark ages (377,000 years until about 1 billion years post Big Bang) during which time the Universe got cold enough for water to form and stars to be born.

5. From 1 billion year until today we saw galaxy’s form and the components of the Universe are much the same as they are today.

Astronomers predict that in the far future we will enter the Stelliferous Era when no more stars are born making the Universe darker and darker as it expands.

Motion in the Universe – Science (Physics) 7

Revision: Gravitational Field Strength “g”

Key Ideas

1. The larger the mass of a planet the greater the gravitational field strength. 2. The larger the radius of the planet the smaller the gravitational field strength at its

surface. 3. Weight, mass and g are linked in the following equation:

Weight=Mass×g4. On Earth, g=10N /kg

Worked Examples

1. What is the weight of an object which has a mass of 552g?

2. If the average giant octopus has a weight of 7.5kN. What is the average mass of a giant octopus?

Motion in the Universe – Science (Physics) 8

Worksheet – Weight, Mass and g

Complete the questions below using the equation you have just learnt. You must show all of your working [equation, substitution, solution and units]

1. How much does an 820kg elephant weigh?

…………………..

2. What is the weight on a 652kg van on earth?

…………………..

3. What is the mass of a book that weighs 5.2N?

…………………..

4. What is mass of an object which weighs 6524N?

…………………..

5. A beaker of water is put on a balance and is found to have a mass of 350. What does it weigh?

…………………..

6. On a distant planet, an object with a mass of 800g will weigh 3kN.a. What is the value of g on this planet?

…………………..

b. What would the weight of a 65kg human be on this planet?

…………………..

Motion in the Universe – Science (Physics) 9

2: Orbital Motion

Knowledge and Understanding QuizUse the knowledge you gained in the previous lessons and since the start of Shell to answer the following questions.

1. What is the name of the force acting downwards on objects on Earth?

……………………………………………………………… (1)

2. What is the definition of a Galaxy and can you give an example?

………………………………………………………………………………………… (2)

3. On Planet A, a mass of 74kg has a weight of 650N. What is the value of ‘g’ on this

planet?

…………………………………………………………………………………………

…………………………………………………………………………………………

………………………………………………………………………………………… (3)

4. A block of wood has a mass of 25kg and takes up 0.04m3 of space. What is the

density of the wood?

……………… (3)

5. What is the equation linking mass, velocity and kinetic energy?

(1)

Score [ /10]

Motion in the Universe – Science (Physics) 10

Learning Outcomes:

1. Understand that gravitational force causes objects to move in a circular motion called orbits.

2. Describe and sketch the different orbital shapes for planets and satellites. 3. Describe how the speed of comets change during their orbit around a star.

Gravitational Force

Key Ideas

1. Gravitational Force is the attraction of two objects to each other due to their masses.

2. The size of the Gravitational force between two objects is dependent on the masses of the two objects and the distance between them.

Motion in the Universe – Science (Physics) 11

F1: Demo – Gravitational Force and Orbits

Your teacher is going to demo orbits in the universe.

Use the space below to make sketches and describe whatyou have seen.

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Motion in the Universe – Science (Physics) 12

Health and Safety Check!

Do not lean on the demo. It is not stable.

Marbles may come offthe demo. Be mindfulnot to stand/trip on these

Orbital Shapes

Key Ideas

1. Gravitational Force causes objects in space to move in curved paths called orbits. 2. Planets and comets orbit the Sun 3. Comets and planets have elliptical orbits4. Satellites and moons orbit Planets. 5. Satellites and moons have circular orbits

Motion in the Universe – Science (Physics) 13

3: Orbital Speed

Knowledge and Understanding QuizUse the knowledge you have gained in the previous lessons to answer the following questions.

1. In what direction does Friction act?

……………………………………………………………… (1)

2. Name two planets in our Solar System.

…………………………………………………………………………………………………………………………………………………………………………………… (2)

3. Can you label the objects in the diagram below?

(4)

4. On Planet X, a mass of 750g has a weight of 25N. What is the value of ‘g’ on this

planet?

……………… (3)

Score [ /10]

Learning Outcomes:

1. Use and rearrange the equation:

s=dt

2. Define ‘orbital speed’3. Rearrange and identify the terms in the equation:

v=2×π×rT to calculate orbital speed.

Motion in the Universe – Science (Physics) 14

Sun Planetor or

Speed, Distance and Time

Key Ideas

1. Speed, Distance and Time are linked in the following equation:

Average Speed=DistanceTravelledTimeTaken

2. Pay attention to the units given in the question – these can be different!

Worked Examples

1. What is the average speed of a cyclist that travels 800m in 60s?

2. How far has a car travelled if it travels at a constant speed of 10m/s for 2 minutes?

Motion in the Universe – Science (Physics) 15

Worksheet – Speed, Distance and Time

Complete the questions below using the equation you have just learnt. You must show all of your working [equation, substitution, solution and units]

1. Calculate the average speed of a car that travels 600m in 60 seconds.

…………………..

2. Calculate the average speed of a train that travels 4000m in 80 seconds.

…………………..

3. Calculate the average speed of a bus that travels 2500m in 500 seconds.

…………………..

4. How far, in meters, will a car travel in 20 seconds at an average speed of 20 m/s?

…………………..

5. How far, in meters, will a train travel in 500 seconds at an average speed of 25 m/s?

…………………..

6. How far, in meters, will a rocket travel in 3 seconds at an average speed of 10000 m/s?

…………………..

7. How long, in seconds, should a car take to travel 500m at an average speed of 25 m/s?

…………………..

Motion in the Universe – Science (Physics) 16

8. How long, in seconds, should a rocket take to travel 1000000m at an average speed of 20000 m/s?

…………………..9. Calculate the average speed of a bus that travels 25km in 900 seconds.

…………………..10. How long, in seconds, should a car take to travel 500km at an average speed of 20

m/s?

…………………..11. How far, in meters, will a cyclist travel in 4 minutes at an average speed of 8 m/s?

…………………..12. How long, in hours, should a car take to travel 600km at an average speed of 25

m/s?

…………………..13. How far, in kilometres, will a rocket travel in 1 minute at an average speed of 5 km/s?

…………………..14. Calculate the average speed (in m/s) of a cyclist that travels 60km in 5 hours.

…………………..

Motion in the Universe – Science (Physics) 17

Deriving Orbital Speed

Rearranging the Equation

Key Ideas

1. The orbital speed equation is another way of writing:

Speed=DistanceTime

2. The distance travelled during orbit is a circle with circumference of 2×π×radius of orbit .

3. T is the time period (the time it takes to do one complete orbit.)

Motion in the Universe – Science (Physics) 18

4. Orbital speed, orbital radius and Time Period are linked in the equation:

orbital speed=2×π ×radiusTime Period

Worked Examples

1. Mercury orbits the sun with a radius of 57.9 million kilometres in 8 days. What is the orbital speed of Mercury in km/s?

2. Saturn orbits the sun with a radius of 1433 million kilometres in 10759 days. What is the orbital speed of Saturn? Give an appropriate unit.

3. Hyperion, one of Saturn’s moons, has an orbital speed of 5.1 km/s and has an orbital period of 21 days. What is the orbital radius of Hyperion?

4. Ceres, a dwarf planet in the asteroid belt, has an orbital speed of 18 km/s and an orbital radius of 410,000,000 km. What is the orbital period of Ceres?

Motion in the Universe – Science (Physics) 19

Worksheet – Orbital Speed

Complete the questions below using the equation you have just learnt. You must show all of your working [equation, substitution, solution and units]

The Equation for Orbital Speed is:

v=2×π ×rT

1. Mars orbits the sun with a radius of 230 million kilometres in 687 days. What is the orbital speed of Mars in km/s?

…………………..

2. Neptune orbits the sun with a radius of 4500 million kilometres in 60,000 days. What is the orbital speed of Neptune in km/s?

…………………..

3. Venus orbits the sun with a radius of 108 million kilometres in 225 days. What is the orbital speed of Venus? Give an appropriate unit.

…………………..

4. Uranus orbits the sun with a radius of 4,500 million kilometres in 165 years. What is the orbital speed of Uranus? Give an appropriate unit.

Motion in the Universe – Science (Physics) 20

…………………..

5. The Earth orbits the sun with a radius of 150 million kilometres. What is the orbital speed of Earth in km/s?

…………………..

6. The Moon has an orbital period of 27.3 days and is 384,400 km from the Earth’s surface. The radius off the Earth is 6400km.

a. Sketch a diagram showing the Earth and the Moon, and label the orbital radius.

b. Calculate the Orbital Speed of the Moon.

…………………..

7. A geostationary satellite is at a height of 125 000 km above the Earth’s surface. What is the speed of the geostationary satellite?

Motion in the Universe – Science (Physics) 21

…………………..

Harder

8. A different geostationary satellite is travelling at a speed 7.8km/s above the Earth’s surface. At what height above the Earth’s surface is it orbiting? Remember the Earth’s radius is 6400km.

…………………..

9. A satellite is in orbit 275km above the Earth’ surface and is travelling at a speed of 9.4km/s, what is the satellites orbital period?

…………………..

10. Saturn’s moon, Titan, orbits at a height of 1,221,860km. Saturn has a radius of 58,000 km. It takes approximately 16 days to complete one orbit. What is the orbital speed for Titan?

…………………..

Motion in the Universe – Science (Physics) 22

Motion in the Universe – Science (Physics) 23

Stretch Worksheet – Measuring Distance in Space

In Astronomy, it is difficult for us to measure in conventional values such as meters or kilometres. Instead Scientists measure in the ‘Light Year’.

Use your MacBook and/or Textbooks to research the Light Year and attempt to answer the following questions.

What is the Speed of Light? What is the Light Year? (Can you work out how far it is in meters?) How wide do Scientists think the Milky Way Galaxy is? (How far is that in

kilometres?)

[Stuck: Try visiting the websites below to get you started!]

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https://www.sciencealert.com/why-is-the-speed-of-light-the-speed-of-light

http://earthsky.org/space/what-is-a-light-year

https://www.popsci.com/science/article/2013-04/cool-galaxy-size-comparison-chart

Motion in the Universe – Science (Physics) 24

Stretch Worksheet – Black Holes

Black Holes are something of an Enigma inspiring a number of Science Fiction works including the 2014 award winning film ‘Interstellar’.

Use your MacBook to do some research to see if you can come up with answers to some of the more frequently asked questions about Black Holes.

1. Is it possible for black holes to lead to other universes?…………………………………………………………………………………………………..…………………………………………………………………………………………………..…………………………………………………………………………………………………..…………………………………………………………………………………………………..…………………………………………………………………………………………………..…………………………………………………………………………………………………..…………………………………………………………………………………………………..…………………………………………………………………………………………………..

2. What happens to all the stuff that gets sucked into the black hole?…………………………………………………………………………………………………..…………………………………………………………………………………………………..…………………………………………………………………………………………………..…………………………………………………………………………………………………..…………………………………………………………………………………………………..…………………………………………………………………………………………………..…………………………………………………………………………………………………..…………………………………………………………………………………………………..

3. What would happen if two black holes got too close together?…………………………………………………………………………………………………..…………………………………………………………………………………………………..…………………………………………………………………………………………………..…………………………………………………………………………………………………..…………………………………………………………………………………………………..…………………………………………………………………………………………………..…………………………………………………………………………………………………..…………………………………………………………………………………………………..

4. Could a black hole's gravity be reversed so that it spit everything back out into the universe?…………………………………………………………………………………………………..…………………………………………………………………………………………………..…………………………………………………………………………………………………..…………………………………………………………………………………………………..…………………………………………………………………………………………………..…………………………………………………………………………………………………..…………………………………………………………………………………………………..…………………………………………………………………………………………………..

Motion in the Universe – Science (Physics) 25

Motion in the Universe

Past Paper Questions

Motion in the Universe – Science (Physics) 26

Q1.

The diagram shows the orbits of some objects in the Solar System.

(a) (i) Path X is the orbit of a(1)

   A    comet

   B    galaxy

   C    planet

   D    star

(ii) Path Y is the orbit of a(1)

   A    comet

   B    galaxy

   C    planet

   D    star

(b) The objects are held in orbit by(1)

   A    electrostatic force

   B    frictional force

   C    gravitational force

   D    magnetic force

(Total for question = 3 marks)

Motion in the Universe – Science (Physics) 27

Q2.

Hubble and Kepler are the names of two space telescopes.

(a) The Hubble telescope is in a circular orbit around the Earth.The Kepler telescope is in a circular orbit around the Sun.(i) The orbit of the Hubble telescope is most like the orbit of a

(1)   A    comet

   B    moon

   C    planet

   D    star

(ii) The orbit of the Kepler telescope is most like the orbit of a(1)

   A    comet

   B    moon

   C    planet

   D    star

(iii) The force that keeps space telescopes in orbit is(1)

   A    friction

   B    gravity

   C    lift

   D    upthrust

(b) Space telescopes are used to study galaxies.

Motion in the Universe – Science (Physics) 28

Use words from the box to complete the sentences below.Each word may be used once, more than once, or not at all.

(i) There are billions of stars in the galaxy called the .................................................................... .

(1)(ii) There are billions of galaxies in the .................................................................... .

(1)

(c) Which of these is nearest to the Earth?(1)

   A    the surface of the Moon

   B    the surface of the Sun

   C    the centre of the Solar System

   D    the centre of the Universe

(d) Gravitational field strength is measured in(1)

   A    kg/N

   B    kg/N2

   C    N/kg

   D    N/kg2

(Total for question = 7 marks)

Motion in the Universe – Science (Physics) 29

Q3.

This question is about the Solar System.

(a) The object at the centre of our Solar System is(1)

   A    a comet

   B    the Earth

   C    the Moon

   D    the Sun

(b) Earth and Mars are planets in our Solar System.The table shows some data for these planets.

(i) Calculate the orbital speed of Mars in km / day.(2)

speed = ...................................... km / day

(ii) The distance between Earth and Mars varies between 100 million km and400 million km.

Explain why this distance is not constant.You may draw a diagram to help your answer.

(2)

      .............................................................................................................................................

      ............................................................................................................................................

Motion in the Universe – Science (Physics) 30

.

      .............................................................................................................................................

(c) Visible light from Mars reaches the Earth.The speed of light is 300 000 km/s.

(i) Show that when the planets are 170 000 000 km apart, it takes about 600 s forlight to travel this distance.

(3)

(ii) Scientists land a remote-controlled vehicle on Mars.

The vehicle sends images back to Earth showing its surroundings on Mars.

Sometimes these images show rocks ahead that could damage the vehicle.

A scientist on Earth sends radio signals that control this vehicle.

The speed of the vehicle is limited to 0.04 m/s.

Suggest why the speed is kept low.(2)

      .............................................................................................................................................

      .............................................................................................................................................

      .............................................................................................................................................

      .............................................................................................................................................

      .............................................................................................................................................

     ..............................................................................................................................................

 

Motion in the Universe – Science (Physics) 31

(Total for question = 10 marks)

Motion in the Universe – Science (Physics) 32

Q4. 

The Moon orbits the Earth.

(a)  State a difference between the orbit of a moon and the orbit of a planet.

(2) .............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

(b)  The radius of the Moon's orbit is 385000 km.

It takes 27 days for the Moon to complete one orbit.Calculate the orbital speed of the Moon.Give a suitable unit.

(3)

orbital speed = ............................ unit ............................

(c)  In 1971, astronaut Alan Shepard hit a golf ball on the surface of the Moon.

The golf ball had a mass of 50 g and he transferred 56 J of energy to it.(i)  State the equation linking kinetic energy, mass and velocity.

(1)

Motion in the Universe – Science (Physics) 33

(ii)  Calculate the initial velocity of the ball.(3)

initial velocity = ............................ m/s

(d)  At its highest point the ball had gained 12 J of gravitational potential energy.

(i)  State the kinetic energy of the ball at its highest point.(1)

kinetic energy = ............................ J

(ii)  State the equation linking gravitational potential energy, mass, g and height.(1)

(iii)  Calculate the maximum height that the ball reached. (gravitational field strength on the Moon, g = 1.6 N/kg)

(2)

maximum height = ............................ m

(e)  Suggest why the ball travelled further on the Moon than it would have done on Earth.

(2) .............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

 

(Total for question = 15 marks)

Motion in the Universe – Science (Physics) 34

Motion in the Universe

Spec Point Notes

Motion in the Universe – Science (Physics) 35

Astrophysics Specification Notes

8.01 use the following units: kilogram (kg), metre (m), metre/second (m/s), metre/second2, (m/s2), newton (N), second (s), newton/kilogram (N/kg)

Remember that mass must ALWAYS be converted to kg, before putting it into any equation

8.02 know that:

• the universe is a large collection of billions of galaxies

• a galaxy is a large collection of billions of stars

• our solar system is in the Milky Way galaxy

The Universe – billions of galaxiesThe Milky Way galaxy contains billions of stars

8.03 understand why gravitational field strength, g, varies and know that it is different on other planets and the Moon from that on the Earth

An object’s gravitational field strength depends on its MASS. A massive object, like a star, will have a very large g-field. The Moon has less mass than the Earth, so its gravitational field is much weaker – approx 1/6th of the Earth’s. This means that we could jump higher on the Moon, and objects would fall more slowly, as they experience a weaker gravitational force.

A planet with a large radius will have a weaker gravitational field at its surface, because the surface is further away from the centre of the planet.

Motion in the Universe – Science (Physics) 36

8.04 explain that gravitational force:

• causes moons to orbit planets

• causes the planets to orbit the Sun

• causes artificial satellites to orbit the Earth

• causes comets to orbit the Sun

According to Newton, there is an attractive gravitational force between any two objects– pulling them together. E.g. the planets and comets experience an attractive force towards the Sun. Moons and artificial satellites are attracted to their planets, and so are pulled towards them.This gravitational force keeps them moving in curved paths called orbits. The Moon does not crash into the Earth, and the planets do not crash into the Sun because they are moving.

8.05 describe the differences in the orbits of comets, moons and planets

Comets have highly elliptical orbits, with the Sun at one focus. When they come in close to the Sun they speed up, due to the larger gravitational force on them. They also

develop bright tails that point away from the centre of the Sun. These are caused by tiny ice crystals that melt and break off from the comet and reflect the bright light of the Sun.Moons have circular orbits and planets orbit in slightly squashed circles, called ellipses.

Motion in the Universe – Science (Physics) 37

8.06 use the relationship between orbital speed, orbital radius and time period:

orbital speed=2×π ×orbitalradiustime period

v=2×π×rT

1.18 know and use the relationship between weight, mass and gravitational field strength:

Weight [Newtons] = mass [kilograms] × gravitational field strength [10N/kg]

W = m × g1.04 know and use the relationship between average speed, distance moved and time

taken:

Average speed = distance moved/time taken

s=dt

Motion in the Universe – Science (Physics) 38