Practice portal › Laws of Motion › Conservation of Linear Momentum

A bomb of mass 30 kg at rest explodes into two pieces of masses 18 kg and 12 kg. The velocity of 18 kg mass is 6 m s⁻¹. The kinetic energy of the other mass is

Asked in NEET 2005 · Recoil and explosions

Answer: (2) 486 J

Step-by-step solution

Given: a 30 kg bomb at rest splits into 18 kg moving at 6 m s⁻¹ and 12 kg.

Idea: the total momentum stays zero, which fixes the speed of the second piece.

0=18×6+12× v, so 12v=-108 and v=-9 m s⁻¹.

The minus sign only says the pieces fly apart in opposite directions.

K=1/2(12)(9)²=1/2×12×81.

=486 J.

Why the other options are wrong

More Conservation of Linear Momentum questionsAll Conservation of Linear Momentum questions →

Reading this solution needs no sign-in. You only sign in to practise against the clock and keep your progress.

Practise this with a timer