Q1. An object of mass 8.5kg is lifted from the floor to a height of 0.5m at a constant speed.
a) What is the net force acting on the mass?
b) What is the magnitude of the lifting force?
c) How much work is done by the lifting force?
d) How much work is done by the net force?
e) What is the value of the poential energy of the object when it is 0.5m above the floor?
Q2. After the object has been lifted 0.5m, it is released from rest and is allowed to fall freely to the floor.
a) How much work does the gravitational force do on it during the fall?
b) How much potential energy does it lose during its fall?
c) What is its kinetic energy just before it hits the floor?
d) What is its velocity just before it hits the floor?
e) What is its velocity when it has fallen halfway to the floor?
Q3. Suppose that the object is dropped from the same height, but is attached to a parachute.
a) Will the kinetic energy just before it hits the floor be the same, large or smaller than it was? Explain your answer.
b) Is mechanical energy conserved in this case?