Question

An anti-craft shell has been fired and it has a kinetic energy x. It explodes in the air. Then the sum of kinetic energies of all the particles is:
A. x
B. More than x
C. Less than x
D. Zero

Answer 1

Hint: When an anti-craft explodes in the air, chemical energy stored in them changes to kinetic energy, heat energy, etc. The final kinetic energies of all the particles are the sum of these energies.

Complete step by step answer:
An anti-craft is an artillery which is used against enemy aircraft and it is made up of different chemicals. Anti- aircraft warfare is a measure taken to defend a maritime force against attacks by airborne weapons that are launched from aircraft, ships, submarines and also any weapons that are launched from land-based areas.
When an anti-craft shell has been fired with an initial kinetic energy of magnitude x and it explodes in the air into various small particles. These particles also possess a certain amount of energy and the sum of the kinetic energies of all the particles is more than the initial kinetic energy of the anti-craft shell because the chemical energy stored in the shell changes to kinetic energy and due to this energy these particles travel to different directions. The final kinetic energy is the sum of initial kinetic energy and chemical energy stored in them. Thus, the sum of kinetic energies of all the particles is more than the initial kinetic energy i.e., x.

So, the correct answer is “Option B”.

Note:
Ann anti-craft explosion is an example of inelastic collision. In an inelastic collision, momentum is conserved and total energy is not conserved i.eThe final energy of the particles is more than initial kinetic with which it explodes.