Question

It is past midnight and Lucy is sliding down a rope from her third window to meet her friend in order to “work on physics homework.” AS she slides down the rope faster and faster, she becomes worried and gradually tightens her grip on the rope. Thus, the tension in the rope slowly increases, and when it becomes equal to Lucy’s weight.

Answer 1

Apply Newton law:

The net force on the rope is,

Fnet = ma = mg - T

Here, m is the mass, a is the acceleration, g is the acceleraiton due to gravity, and T is the tension.

When weight is equal to tension, then the force is,

ma = mg - T = 0

Hence, the lucky moves with constant speed and work done to get down the rope is zero.