GravityIB MYP Physics: Topic test

20 questions, 54 marks

IB MYP Physics

Gravity topic test

Total 54 marks

Name

Class

Date

1
A shopkeeper in Perth, Australia, hangs a 4.0 kg bag of rice from a spring balance to check it. Take g = 10 N/kg on Earth and 1.6 N/kg on the Moon.
(a)
What is the weight of the bag of rice on Earth?
[1 mark]
A4 N
B0.4 N
C40 N
D400 N
(b)
The bag of rice is taken to the Moon. Which statement is correct?
[1 mark]
AIts mass is still 4.0 kg and its weight is less than 40 N
BIts mass is less than 4.0 kg and its weight is less than 40 N
CIts mass is still 4.0 kg and its weight is still 40 N
DIts mass is more than 4.0 kg and its weight is more than 40 N
(c)
State the name of the instrument used to measure weight and the unit in which weight is measured.
[2 marks]
Total for question 1: 4 marks
2
The Moon travels round the Earth in a nearly circular orbit once every 27 days, and the Earth travels round the Sun.
(a)
Which statement about gravity is correct?
[1 mark]
AIt is a contact force that acts only on moving objects
BIt is a non-contact force that acts between all masses
CIt is a force that pushes objects apart
DIt acts only on the surface of a planet, not in space
(b)
What happens to the gravitational force between two objects as the distance between them increases?
[1 mark]
AIt increases
BIt stays the same
CIt increases and then decreases
DIt decreases
(c)
Explain why the Moon does not fall into the Earth, even though gravity pulls it towards the Earth.
[2 marks]
Total for question 2: 4 marks
3
A probe has a mass of 150 kg. It is tested on Earth, where the gravitational field strength is 10 N/kg, before being sent to Jupiter, where the field strength at the cloud tops is 25 N/kg.
(a)
Calculate the weight of the probe on Earth and the weight it would have at the cloud tops of Jupiter.
[3 marks]
(b)
Explain what is meant by a gravitational field, and why the probe has the same mass but a different weight on Jupiter.
[4 marks]
Total for question 3: 7 marks
4
A space agency in Kourou, French Guiana, launches two satellites into circular orbits around the Earth. Satellite X orbits 500 km above the surface and completes one orbit every 95 minutes at a speed of 7.6 km/s. Satellite Y orbits 36 000 km above the surface and completes one orbit every 24 hours at a speed of 3.1 km/s. The agency also plans a one-year mission for astronauts on a space station in a low orbit.
(a)
Describe how the orbital speed and the orbital period change with height, explain the pattern, and predict the speed of a satellite that orbits 20 000 km above the surface.
[6 marks]
(b)
Discuss whether the benefits of keeping astronauts in orbit for a year outweigh the drawbacks. Refer to what happens to the astronauts' weight in orbit.
[6 marks]
Total for question 4: 12 marks
5
A newton meter in a laboratory in Edinburgh shows 35 N when a rock sample hangs from it on Earth, where g = 10 N/kg. On the Moon, g = 1.6 N/kg.
(a)
What is the mass of the rock?
[1 mark]
A3.5 kg
B350 kg
C35 kg
D0.35 kg
(b)
What would the same newton meter read for the rock on the Moon?
[1 mark]
A35 N
B21.9 N
C56 N
D5.6 N
(c)
Another rock has a weight of 16 N on the Moon. Calculate its mass.
[2 marks]
Total for question 5: 4 marks
6
On the Moon, which has no atmosphere, an astronaut drops a hammer and a feather together from the same height.
(a)
What happens?
[1 mark]
AThe hammer lands first
BThey land at the same time
CThe feather lands first
DNeither falls
(b)
Which force is the only force acting on the falling objects?
[1 mark]
AAir resistance
BUpthrust
CTheir weight, the pull of the Moon's gravity
DFriction with the ground
(c)
Explain why an astronaut can jump much higher on the Moon than on Earth.
[2 marks]
Total for question 6: 4 marks
7
A space agency measures the gravitational force of the Earth on a 500 kg probe at three distances from the Earth's centre. At the surface, 6400 km from the centre, the force is 5000 N. At 12 800 km from the centre it is 1250 N. At 19 200 km from the centre it is 556 N.
(a)
Describe how the gravitational force on the probe changes as its distance from the centre of the Earth increases. Use figures from the data.
[3 marks]
(b)
Use the pattern in the data to predict the gravitational force on the probe at 25 600 km from the centre of the Earth.
[4 marks]
Total for question 7: 7 marks
8
A student in Lima, Peru, wants to find out whether an object weighs less at the top of a high mountain than at sea level. She has a 1.0 kg mass and a newton meter whose smallest scale division is 0.1 N. At sea level the meter reads 9.8 N. The mountain summit is 4 km higher, and the radius of the Earth is about 6400 km.
(a)
Write a hypothesis for her investigation, with a scientific reason. Identify the independent, dependent and one control variable, and outline a method.
[6 marks]
(b)
Evaluate whether her newton meter is suitable for testing the hypothesis, and suggest one improvement.
[6 marks]
Total for question 8: 12 marks

End of questions

Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).