A disc is freely rotating with an angular speed on a smooth horizontal plane. If it is hooked at a rigid page and rotates without bouncing about a point on its circumference. Its angular speed after the impact will be equal to

a) |
b) |
c) |
d) |
None of these |

A disc is freely rotating with an angular speed on a smooth horizontal plane. If it is hooked at a rigid page and rotates without bouncing about a point on its circumference. Its angular speed after the impact will be equal to

a) |
b) |
c) |
d) |
None of these |

1 Answer

127 votes

**(b)**

During the impact, the forces pass through point . Therefore, the torque produced by it about is equal to zero

Consequently, the angular momentum of the disc about , just before and after the impact, remains the same

…(i)

Where angular momentum of the disc about just before the impact

angular momentum of the disc about just after the impact

Just before the impact, the disc rotates about . But just after the impact, the disc rotates about

127 votes

127