Question

Give three example of motion of centre of mass

Answer 1

Answer:

uniform disc, bolo toss, tailgating for football

Answer 2

Three examples of motion of center of mass are:

• A radium nucleus into the nucleus of radon and an alpha particle.

1. All the forces leading to the decay are internal, as the external forces are negligible. If the decaying radium nucleus is at rest the product of decay moves back to back, so that their center of mass remains at rest.
2. But if the decaying radium nucleus is moving along a straight line, the products move in different directions so that the center of mass keeps moving with the same velocity along the straight path the original decaying nucleus is moving.

• The moon revolving around the earth in a circular orbit:

1. We know that the moon revolves around the earth in a circular orbit. The force of attraction between the moon and earth is the gravitational force which is again an internal force.
2. To eliminate the chances of the moon and earth colliding with each other due to the presence of internal forces, we assume that both moon and earth are revolving around their center of mass, such that they are always at the opposite side of their center of mass.

• The center of mass of a uniform disc shape would be at its center.