Andrea rides her bicycle at a speed of 10 m/s. She and the bike have a combined mass of 50 kg.

a. If she uses her brakes to slow down to 5 m/s, how much energy is converted to heat?

b. Andrea has a particularly old bike, and she has not lubricated the chain or gears. This causes friction inside the gears as she rides. She begins coasting on flat ground at a speed of 10 m/s, and after a few seconds is only going 8 m/s. How much energy has been converted to heat?

c. Andrea is going 10 m/s toward a hill. She coasts up the hill without pedaling. If friction causes 10% of her energy to be converted to heat inside the gears, how high up the hill will she be able to coast?