Question

A smooth wedge A is fitted in a chamber hanging from a fixed ceiling near the earth's surface.. A block B placed at the top of the wedge takes time T to slide down the length of the wedge. If the block is placed at the top of the wedge and the cable supporting the chamber is broken at the same instant, the the block will

(a) take a time longer than T to slide down the wedge

(b) take a time shorter than time T to slide down the wedge

(c) remain at the top of the wedge

(d) Jump off the wedge.

The answer is (a).

Answer 1

c) remain at the top of the wedge

The only thing that makes anything slide down a wedge is gravity. Since both wedges are under the influence of the same gravity there is not net force on wedge B to make it slide down wedge A if the string breaks and they both are falling from gravity.

Think of it like this. If you were sitting at the top of a sliding board (which is a wedge) you go down it from gravity pushing you. If you were up in the air and dropped you and the sliding board together, you and the board would drop together...gravity isn't going to push you down faster than the sliding board which is also falling.