In each row, an object moves in a circle. Which... | Physics (9-1) 0972 | Paper 2 Mock 01 | Multiple Choice (Extended)

Question 1 Report

In each row, an object moves in a circle. Which row correctly identifies the force that provides the centripetal force?

	Situation	Force providing centripetal force
A	satellite orbiting the Earth	thrust from rocket engines
B	car turning on a flat road	friction between the tyres and the road
C	electron orbiting a nucleus	gravitational force on the electron
D	ball on a string in a horizontal circle	the weight of the ball

Answer Details

For each situation, the centripetal force must be identified:

Satellite orbiting Earth: the centripetal force is provided by gravitational attraction, not rocket thrust. Satellites in orbit need no engines.
Car turning on a flat road: the centripetal force is provided by friction between the tyres and the road. This is correct.
Electron orbiting a nucleus: the centripetal force is provided by electrostatic (Coulomb) attraction between the negative electron and the positive nucleus, not gravity.
Ball on a string in a horizontal circle: the centripetal force is provided by the tension in the string, not the weight of the ball.

The row identifying friction for a car on a flat road is correct.