Question

After a totally inelastic collision, two objects of the same mass and same initial speeds are found to move together at half of their initial speeds. The angle between the initial velocities of the objects is
A. `30^(@)`
B. `60^(@)`
C. `45^(@)`
D. `37^(@)`

Answer 1

Correct Answer - A
Let angle between initial velocities be `pi-theta` and the situation is an showin in figure. Conserve the momentum along `x`- and `y`-direction.

`mv-mvcostheta-2mv/2cosalpha`, for `X`-axis
`mv sintheta=2mv/2sinalpha` for `y`-axis
Solving above equation `theta=60^(@)`
Required angle `=pi-60^(@)=120^(@)`