Question

A girl on a sled with a total mass of 90kg starts from an elevation of 100meters. At the bottom of the run her speed is 30m/s. How much energy in joules was lost due to
friction?

Answer 1

Potential energy drop = m g h =90*9.81*100
= 88,290 Joules

Kinetic energy = (1/2) m v^2 = 45(900) = 40,500 Joules
so
loss to heat = difference = 47,790 Joules