9J End of Unit Test

Name Class
9
1 What is the name of the force that pulls you downwards?
J
[1 mark]
2 This diagram shows the direction that someone in the UK would describe as ‘down’,
and the direction that someone living in South Africa would describe as ‘down’.

Why are the directions different?

[1 mark]
3 Danny has a mass of 55 kg. What is his weight? The strength of gravity on the
Earth is 10 N/kg. Give the unit.

[2 marks]
4 The diagram shows a spacecraft orbiting above a moon.

a Draw arrows on the diagram to show the force on the spacecraft and the force
on the moon.
[2 marks]

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9J End of Unit Test (continued)

b How would the size of the forces change if the spacecraft had twice as much mass?

[1 mark] 9
c How would the size of the forces change if the spacecraft moved further away?
J

[1 mark]
5 The table shows the strength of gravity of four of Jupiter’s moons.

Moon Gravity at the surface of the moon (N/kg)

a Which moon would you expect to have the biggest mass?

[1 mark]
b Explain your answer to part a.

[1 mark]
c An astronaut has a mass of 900 kg in his spacesuit. What would his weight
be on Ganymede? Show your working.

[2 marks]
6 A satellite moves in a circular orbit around the Earth.
a It does not need to use its engine to keep moving. Why not?

[1 mark]
b What causes its path to be circular?

[1 mark]
7 A satellite is launched to help scientists investigate the amount of plankton living in
all the world’s oceans. It will do this by taking photographs of the oceans from a
height of 300 km. It is put into a polar orbit.

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 9J End of Unit Test (continued)

a Describe this kind of orbit.

9 [2 marks]
J b Why is this the most suitable orbit for the satellite?

[2 marks]
c Describe two other uses for satellites.

[2 marks]
8 Which of these descriptions matches our current model of the Solar
System? Tick one box.
The Sun and Moon and the planets all move around the Earth in
circular orbits.
The planets and the Moon all move around the Sun in elliptical orbits.
The planets all move around the Sun in elliptical orbits.
The planets all move around the Sun in circular orbits.
[1 mark]
9 One old idea was that the heavens were made by God, so that the Earth is at
the centre of everything, and everything must be perfect. The planets and stars
were therefore perfect spheres that never changed, and all movement must be
circular, as a circle is a ‘perfect’ shape.
Describe two pieces of evidence that contradicted these views.

[2 marks]

10 What evidence do we have that the planets move in elliptical orbits around the
Sun, not in circular orbits?

[2 marks]

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