Physics 5054 · O Level · Motion

Motion — practice question

Fig. 9.1 shows a satellite orbiting the Earth.
(a(i))[2]

The satellite moves at constant speed in a circular orbit. Underline the items in the list below that are scalars: acceleration, force, mass, speed, velocity.

(a(ii).1)[1]

State what is meant by velocity.

(a(ii).2)[1]

Explain why the velocity changes.

(a(iii))[2]

Explain what causes this satellite to follow a circular orbit.

(b(i))[1]

A rocket carries the satellite into orbit. The rocket and fuel together have a combined mass of $40\,000\,\text{kg}$ and a total weight of $400\,000\,\text{N}$. The upward resultant force on the rocket is $50\,000\,\text{N}$. Calculate the thrust produced by the rocket engine.

(b(ii))[2]

Calculate the acceleration of the rocket.

(c(i))[2]

In the first four minutes after take-off, the rocket's acceleration is uniform. State what is meant by a uniform acceleration.

(c(ii))[3]

Fig. 9.3 outlines the rocket's motion during the first 12 minutes. On Fig. 9.4, sketch the rocket's speed-time graph for the first 12 minutes. You do not need to include speed values.

(c(iii))[1]

State how the speed-time graph in (ii) may be used to determine the distance travelled by the rocket.

Worked solution & mark scheme

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