Question

A cyclist is traveling at 10m/s when he comes to a hill. He stops pedaling at the bottom of the hill and lets the bicycle coast up the hill. Assuming no energy is lost to friction and g equals 10m/s2 , what will be the vertical height of the bicycle when it stops coasting?

A. 1m

B. 5m

C. 10m

D. 50m

Answer 1

Given a cyclist is moving with speed 10m/s. at this time before the cyclist stops pedaling, the cyclist will only have kinetic energy(assuming potential at the height of the horizontal road is zero)

Once the cyclist reaches an epitome of height, the cycle will stop coasting and the system will only have a potential energy

By conservation of mechanical energy(in the absence of friction)

Total energy of cyclist before coasting =Total energy of cyclist after stopping

ie,

(here, v is the inital speed of the cyclist, anf h is the vertical height reached by the cycle)

Hence,