A solid cylinder of mass `50 kg` and radius `0.5 m` is free to rotate about the horizontal axis. A massless string is wound round the cylinder with one end attached to it and other end hanging freely. Tension in the string required to produce an angular acceleration of `2` revolution `s^(-2)` is

Options

A. 78.5N
B. 157N
C. 25N
D. 50N

Answer

B

Explanation

`tau= I alpha = T r`
`rArr T= (I alpha)/(r)`
`= (mr^(2))/(2) xx (alpha)/(r)= (m alpha r)/(2)`
`= 50 xx 0.5 xx 2 xx 2pi = 157N`