A child is standing on the edge of a merry-go-round that has the shape of a disk, as shown in the figure. The mass of the child is 40 kg. The merry-go-round has a mass of 200kg and a radius of 2.5 m, and it is rotating with an angular velocity of `omega=2.0` radians per second. The child then walks slowly towards the centre of the merry-go-round. What will be the final angular velocity of the merry-go-round when the child reaches the centre? (The size of the child can be neglected)

Options

A. 2.0 rad/s
B. 2.2 rad/s
C. 2.4 rad/s
D. 2.8 rad/s

Answer

4

Explanation

By conservation of angular momentum
`(1/2 MR^(2)+mR^(2)) w_(0)=1/2 MR^(2) omega`