Two cyclists of identical mass each climb a hill that raises them 60 m above their…
PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
Two cyclists of identical mass each climb a hill that raises them 60 m above their starting point. Both cyclists begin the climb with negligible speed at the base and finish with negligible speed at the top. The chemical energy that each cyclist’s body converts into mechanical work during the climb is 2.5 × 10⁵ J.
• Cyclist A reaches the summit in 600 s.
• Cyclist B reaches the summit in 400 s.
Assume air resistance and rolling resistance are negligible compared to the energy required for the climb itself.
(a) Determine the average mechanical power output for Cyclist A during the climb.
(b) Determine the average mechanical power output for Cyclist B during the climb.
(c) Compute the ratio of Cyclist B’s average power output to Cyclist A’s average power output.
(d) If both cyclists convert chemical energy to mechanical work with the same efficiency, discuss which cyclist’s body must release metabolic energy at a greater rate (power) and explain why.