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 ms^(-1)`.The kinetic energy of the larger fragment is

Options

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

Answer

A

Explanation

Momentum is conserved.
`therefore` Mass of fragments are as ` 2 : 3`
Total mass = 20 kg
`therefore` Larger fragment = 12 kg
`therefore` Smaller fragment = 8 kg
`therefore 8 xx 6 = 12 xx v`
or v = 4 = velocity of larger fragment.
`therefore` Kinetic energy = `(1)/(2)mv^(2) = (1)/(2) xx 12 xx (4)^(2)`
= 96 J.