A ball of mass `10 kg` strikes another ball of mass `25 kg` at rest. If they separated in mutually perpendicular directions then the coefficient of restitution is:

Options

A. `(10)/(25)`
B. `(25)/(10)`
C. `1`
D. `0.8`

Answer

A

Explanation

From the definition of `''e''`
`e=(v')/(u cos alpha)`i.e., `v'=eu cos alpha`.....(1)

From conservation of linear momentum, compound along the common normal `AB`
`10u cos alpha=25'v`……(2)
`(1)/(25)=(e)/(10), :. e=(10)/(25)=0.4`
So choices (b), (c ) and (d) are wrong.