A metal ball of mass 2 kg moving with a velocity of `36km//h` has a head on collision with a stationery ball of mass 3 kg. If after the collision, the two balls move together, the loss in kinetic energy dur to collision is

Options

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

Answer

B

Explanation

`m_1 =2kg , u_1 = 36 xx 5/18 = 10 m//s`
`m_2 = 3kg , u_2 =0`
`m_1u_1+m_2u_2=(m_1+m_2)vimplies v(2xx10)/5 = 4m//s`
Loss in K.E. `=1/2m_1u_1^2-1/2(m_1+m_2)v^2`
`=1/2xx2 xx100 -1/2 xx 5 xx 16 = 60 J`