Question

An asteroid enters the atmosphere of the earth and breaks into two pieces. One of the pieces is larger than the other. Which of the following is true considering the centre of mass of both the pieces together?

(a) The centre of mass shifts horizontally towards the larger piece

(b) The centre of mass shifts horizontally towards the smaller piece

(c) The centre of mass remains in the same trajectory as before breaking apart of the asteroid

(d) Depends on the velocity of the asteroid

The question was asked in examination.

The doubt is from System of Particles topic in portion System of Particles and Rotational Motion of Physics – Class 11

Answer 1

The correct choice is (c) The centre of mass remains in the same trajectory as before breaking apart of the asteroid

To explain I would say: Since internal forces do not change the position of the centre of mass of a system as their net force is zero, the centre of mass remains in the same trajectory as before breaking apart of the asteroid. However, it is an influential factor for the trajectories of the two pieces after breaking apart.