A body of mass m moving with velocity `3km//h` collides with a body of mass 2m at rest. Now, the coalesced mass starts to move with a velocity

Options

A. 1km/h
B. 2km/h
C. 3km/h
D. 4km/h

Answer

A

Explanation

Applyiing law of conservation of momentum,
`m_(1)u_(1)+m_(2)u_(2)=(m_(1)+m_(2))v`
or,`m_(1)u_(1)=(m_(1)+m_(2))v" "(because u_(2)=0)`
`impliesm((3xx1000))/(3600)3m(v)impliesv=(1000)/(3600)m//s=1km//hr`