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

Answer

B

Explanation

`tau=I alpha=T r`
implies `T=(I alpha)`
= `(mr^(2))/(2)xx(alpha)/(r)=(m alpha r)/(2)`
= `50xx0.5xx2xx2pi =157` N