Concepts Of Physics MCQ Edition [Volume 1]PhysicsCentre of Mass, Linear momentum, Collision
A heavy ring of mass m is secured on the periphery of a light circular disc. A small particle of equal mass is secured at the centre of the disc. The system is revolved such that the centre moves in a circle of radius r with a uniform speed v . We can conclude that an external force
Options
- Aof mv^2 r must act on the central particle
- Bof 2mv^2 r must act on the system
- Cof 2mv^2 r must act on the ring
- Dof 2mv^2 r must act on the central particle
Correct answer
B. of 2mv^2 r must act on the system
Step-by-step solution
The system consists of a heavy ring of mass m and a small particle of mass m . Since the ring is secured on the periphery of the circular disc, its centre of mass lies at the geometric centre of the disc. The small particle is also secured at the centre of the disc. Therefore, the centre of mass of the entire system coincides with the centre of the disc. The total mass of the system is: M = m_ ring + m_ particle = m + m = 2m The centre of the disc (which is the centre of mass of the system) moves in a circle of rad