Physics (AS & A Level) · May / June 2021 · Paper 13 · Question 11

A steel ball is falling at a constant (terminal) speed in still air. The forces acting on the ball are upthrust, viscous drag and weight. What is the order of increasing magnitude of these three forces?

1. Aupthrust → viscous drag → weight
2. Bviscous drag → upthrust → weight
3. Cviscous drag → weight → upthrust
4. Dweight → upthrust → viscous drag

As printed in the paper