Physics (AS & A Level) · Oct / Nov 2025 · Paper 12 · Question 17

A student attempts to derive the formula for kinetic energy E_K. She begins by considering an object of mass m that is initially at rest. A constant force F applied to the object causes it to accelerate to final velocity v in displacement s. The kinetic energy gained by the object is equal to the work done on the object by the force F. Which equation does the student not need in order to derive the formula for E_K?

1. AF = ma
2. BW = Fs
3. CE = \frac{1}{2}Fs
4. Dv^2 = u^2 + 2as

As printed in the paper