Question

A spherical ball A of mass 4 kg, moving along a straight line strikes another spherical ball B of mass 1 kg at rest. After the collision, A and B move with velocities `v_1 m s^(-1) and v_2 m s^(-1)` respectively making angles of `30^@ and 60^@` with respect to the original direction of motion of A. The ratio `v_1/v_2` will be
A. `sqrt3/4`
B. `4/sqrt3`
C. `1/sqrt3`
D. `sqrt3`

Answer 1

Correct Answer - A

Applying the law of conservation of linear momentum along a direction perpendicular to the direction of motion (i.e. along y-axis), we get
`0+0 = 4v_1 sin30^@- v_2 sin60^@`
`4v_1 sin30^@ = v_2 sin60^@ or v_1/v_2 =(sin 60^@)/(4sin 30^@)=sqrt3/4`