Gravitational Fields Exam-style MCQs | A-Level Physics OCR

Question 1

A planet has a radius half the Earth's radius and a mass a quarter of the Earth's mass. What is the approximate gravitational field strength on the surface of the planet?

A

1.6 N kg^–1

B

5.0 N kg^–1

C

10 N kg^–1

D

20 N kg^–1

0

/

1

Question 2

The gravitational force between two point-mass objects X and Y is F₁.

The mass of X increases and the distance between X and Y is halved.

Which statement about the new gravitational force F₂ between these two objects is correct?

A

0 < F₂ < 0.25F₁

B

F₂ > 4F₁

C

F₂ = F₁

D

2F₁ < F₂ < 4F₁

0

/

1

Question 3

The distance between the Sun and Mars varies from 2.1 × 10¹¹ m to 2.5 × 10¹¹ m.

When Mars is closest to the Sun, the force of gravitational attraction between them is F.

What is the force of gravitational attraction between them when they are furthest apart?

A

0.71F

B

0.84F

C

1.2F

D

1.4F

0

/

1

Question 4

Two stars of mass M and 4M are at a distance d between their centres.

The resultant gravitational field strength is zero along the line between their centres at a distance y from the centre of the star of mass M.

What is the value of the ratio $\frac{y}{d}$ ?

21

31

32

43

0

/

1

Question 5

A planet has radius R and density $\rho$ . The gravitational field strength at the surface is g.

What is the gravitational field strength at the surface of a planet of radius 2R and density 2 $\rho$ ?

A

2g

B

4g

C

8g

D

16g

0

/

1

Question 6

A planet of mass M and radius R rotates so quickly that material at its equator only just remains on its surface.

What is the period of rotation of the planet?

2 π√G MR

2 π√RG M

2 π√G MR3

2 π√R3G M

0

/

1

Question 7

A spacecraft of mass 1.0 × 10⁶ kg is in orbit around the Sun at a radius of 1.1 × 10¹¹ m.

The spacecraft moves into a new orbit of radius 2.5 × 10¹¹ m around the Sun.

What is the total change in gravitational potential energy of the spacecraft?

A

– 6.76 × 10¹⁴ J

B

-3.38 × 10¹⁴ J

C

3.38 × 10¹⁴ J

D

6.76 × 10¹⁴ J

0

/

1

Question 8

Earth has a mass of 6.0 × 10²⁴kg and a radius of 6,400 km.

A satellite of mass 320 kg is lifted from the Earth’s surface to an orbit 1,200 km above its surface.

What is the change in the gravitational potential energy of the satellite?

A

9.1 × 10² J

B

9.9 × 10⁶ J

C

3.2 × 10⁹ J

D

3.8 × 10⁹ J

0

/

1

Question 9

Which of the following statements about Newton’s law of gravitation is correct?

Newton’s gravitational law explains

A

the origin of gravitational forces

B

why a falling satellite burns up when it enters the Earth’s atmosphere

C

why projectiles maintain a uniform horizontal speed

D

how various factors affect the gravitational force between two particles

0

/

1

Question 10

The distance between the Sun and the Earth is 1.5 × 10¹¹ m.

What is the gravitational force exerted on the Sun by the Earth?

A

3.5 × 10²² N

B

1.7 × 10²⁶ N

C

5.3 × 10³³ N

D

8.9 × 10⁵⁰ N

0

/

1