Question
Physics Question on System of Particles & Rotational Motion
When an explosive shell travelling in a parabolic path under the effect of gravity explodes in the mid air, the centre of mass of the fragments will move
A
vertically downwards
B
along the original parabolic path
C
vertically upwards and then vertically downwards
D
horizontally followed by parabolic path
Answer
along the original parabolic path
Explanation
Solution
The forces leading to the explosion are internal forces. They contribute nothing to the motion of the centre of mass. The total external force, namely the force of gravity acting on the shell is the same before and after the explosion. Therefore, the centre of mass of the fragments of the shell continues along the same parabolic-path as it would have followed, if there were no explosion as shown in figure. 