posted by ryland .
A 7 kg purse is dropped from the top of the Leaning Tower of Pisa and falls 53 m before reaching the ground with a speed of 17 m/s. What was the average force of air resistance?
loss of potential energy = m g h
gain of kinetic energy = (1/2)m v^2
difference = work against friction
which = F * 53 neters