Question

A bomb of mass 9 kg initially at rest explodes into two pieces of masses 3 kg and 6 kg. If the kinetic energy of 3 kg mass is 216J, then the velocity of 6kg mass will be 

(1) 4 m/s 

(2) 3 m/s 

(3) 2 m/s 

(4) 6 m/s

Answer 1

(4) 6 m/s

Using conservation of momentum

M₁V₁ = M₂ V₂

3 x V₁ = 6 x V₂ ........ (i)

1/2 x 3 x v²₁ = 216

⇒ V₁ = 12 m/s ; 

V₂ = 6 m/s