1. A 10-kg object is dropped from rest. After falling a distance of 50 m, it has a speed of 26 m/s.

a. Write the expression for the change in mechanical energy caused by the dissipative (air) resistive force on the object during this descent.
b. Calculate the energy.

2 answers

a = drop in potential energy = m g h
b = gain in kinetic energy = (1/2) m v^2

work done by friction = a - b
-1.5kj