A disc of radius R rotates from rest about a vertical axis with a constant angular acceleration such that a coin placed with a tangenitial between a as shown in figure If the coefficient of static friction between the coin and disc is `mu_(s)` .Find the velocity of the before it start sliding relative as the disc

Options

A. `0.1`
B. `0.2`
C. `0.3`
D. `0.4`

Answer

b

Explanation

`f_(1) = mu mg ` friction will provide the necessary contripetal force`f = m omega^(2)r`
`f le f_(1) rArr m omega^(2)r le mu mg`
`rArr mu ge (omega^(2)r)/(g) = (2^(2) xx 50 //100)/(10)`
`rArr mu ge 0.2`