Question

Two objects with masses 4.90 and 2.10 hang 0.800 above the floor from the ends of a cord 7.20 long passing over a frictionless pulley. Both objects start from rest.

Find the maximum height reached by the 2.10 object.

Answer 1

The heavier object will move .8 m down, thelighter will move up an additional .8m.

max height= initial height+movement up.

I am surprised this problem was given in physics.

Answer 2

but how do you find the initial height?

Answer 3

bob, you fail to understand that the tension force has accelerated the lighter object upwards; when the heavier object hits the floor, the lighter object still has upward velocity. the magnitude of this velocity is determined by the magnitude of the tension force.