Question

An elevator is hanging from a strong cable. The elevator is at rest. Compare the force exerted by the cable on the elevator to that exerted by the elevator on the cable. Also, compare the tension in the cable to the weight (mg) of the elevator.

The elevator begins accelerating upwards. Make the same comparisons.

The elevator begins descending at constant velocity. Make the same comparisons.

Answer 1

Here ,

for the elevator is at rest ,

using third law of motion

force exerted by the cable on the elevator is equal

and tension in cable = weight of the elevator

Now , is the elevator is acceleating upwards

using third law of motion

force exerted by the cable on the elevator is equal.

as the elevator is accelerating upwards

tension in the cable is greater than weight of elevator

NOw, for constant descending at constant velocity

using third law of motion

force exerted by the cable on the elevator is equal

and tension in cable = weight of the elevator

Now , is the elevator is acceleating upwards