Question1
An elevator is being lifted up an elevator shaft at a constant speed by a steel cable. All frictional effects are negligible. In this situation, forces on elevator are such that-
a) upward force by the cable is greater than the downward force of gravity.
b) Upward force by the cable is equal to the downward force of gravity.
c) Upward force by the cable is smaller than the downward force of gravity.
d) Upward force by the cable is greater than the sum of the downward force of gravity and a downward force due to the air.
e) None of above. (The elevator goes up because the cable is being shortened, not because an upward force is exerted on the elevator by the cable.)