A metal ball of mass 2 kg moving with a velocity of 36 km./h has a head on collision with a stationary ball of mass 3 kg. If after the collision the two balls move together, the loss in K.E. due to collision is :

Options

A. 140 J
B. 100 J
C. 40 J
D. 60 J

Answer

d

Explanation

According to conservation of momentum,
`m_(1)v_(1)+m_(2)v_(2)=(m_(1)+m_(2))v`
`implies 2xx10+0-(2+3)vimpliesv=4 m//s`
`:.` Loss in K.E. = Initial K.E. - Final K.E.
=`1/2m_(1)u^(2)-1/2(m_(1)+m_(2))v^(2)`
=`1/2xx2xx100-1/2xx5xx16=100-40=60 J`.