A cyclist rides on a straight level road where the total resistive force (due to air…
PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
A cyclist rides on a straight level road where the total resistive force (due to air and rolling friction) is 120N.
(i) Define power and state its SI unit.
(ii) The cyclist maintains two different constant speeds on consecutive rides: 6ms−1 and 9ms−1, facing the same resistive force each time. Without performing any numerical calculation, explain how the power required at 9ms−1 compares with that at 6ms−1.
(iii) If the cyclist covers the same distance on both rides, explain why the total work done against the resistive force is the same in each case even though the power outputs differ.