Question

At a certain height a shell at rest explodes into two fragments. One of the fragments receives a horizontal velocity ‘u’ and other receives a horizontal velocity ‘3u’.  The time interval after which the velocity vectors will be inclined at 90º to each other is​

Answer 1

Answer:

A shell at rest explodes

According to the problem two fragments of shell are created after the exploding which is done an external force. As here is no external force therefore the momentum will be conserved. this says that both fragments are opposite to each other with same speed. Let after t time the fragments will 120 degree to each other.