A shell of mass `20 kg` at rest explodes into two fragments whose masses are in the ratio `2 : 3`. The smaller fragment moves with a velocity of `6 m//s`. The kinetic energy of the larger fragment is

Options

A. 96 J
B. 216 J
C. 144 J
D. 360 J

Answer

A

Explanation

`{:(m_1=2m,m_2=3m,implies2m+ 3m = 20 implies m=4kg),(= 8kg,=12kgm,):}`
`m_1v_1 = m_2v_2 =0`
`impliesv_2 = (-m_1v_1)/(m_2) = -(2mxx6)/(3m) =-4m//s`
`(KE)_2 =1/2 xx12 xx(-4)^2 = 96 J`