Question
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
96 J
216 J
144 J
360 J
Solution
A.
96 J
Total mass of the shell = 20 kg
Ratio of the masses of the fragments are 8 kg and 12 kg
Now according to the conservation of momentum
m1 v1 = m2 v2
∴ 8 × 6 = 12 × v
v (velocity of the larger fragment) = 4 m/s
Kinetic energy =
=
Kinetic energy = 96 J
