increase in potential energy = A = m g h
increase in kinetic energy = B = (1/2) m v^2
total work done by motor = A+B
work done by gravity = -A
F = (A+B)/15.1
A construction crew pulls up an 87.5-kg load using a rope thrown over a pulley and pulled by an electric motor. They lift the load 15.1 m and it arrives with a speed of 15.6 m/s having started from rest. Assume that acceleration was not constant.
a. How much work (J) was done by the motor?
b. How much work was done by gravity?
c. What constant force N could the motor have exerted to cause this motion?
2 answers
By the way, do not forget g (9.81 m/s^2) in m g h
1 answer