Rosie asks:

“I can’t figure out how to solve this problem:

The total mass of a motorcycle and rider is 250kg. During braking, they are brought to rest from 16m/s in a time of 10s. What is the maximum amount of energy converted into heat by the brakes?

I don’t know whether to use WD = F x d or another set of formula?”

Answer:

This question is based on conservation of energy. The heat energy liberated is equal to the change in kinetic energy. Since the bike is brought to rest, the change in KE is equal to its initial KE.

The answer assumes that the entire KE is converted into heat energy alone.

Heat =Change in KE =