Two identical small balls, each of mass , are connected by a massless and inextensible string of length and placed on a smooth horizontal plane. An external agent starts pulling the string from its mid-point along -axis with velocity as shown in Fig. When the separation between the two balls reduces to then the speed of each ball will be

a) |
b) |
c) |
d) |
None of the above |

Two identical small balls, each of mass , are connected by a massless and inextensible string of length and placed on a smooth horizontal plane. An external agent starts pulling the string from its mid-point along -axis with velocity as shown in Fig. When the separation between the two balls reduces to then the speed of each ball will be

a) |
b) |
c) |
d) |
None of the above |

1 Answer

127 votes

**(b)**

Using conservation of angular momentum about the midpoint, we can find the velocity of each ball relative to the midpoint. i.e.

Resultant velocity of ball= velocity of midpoint + velocity of ball w.r.t. midpoint

or

127 votes

127