A disc has mass 'M' and radius 'R'. How much tangential force should be applied to the rim of the disc, so as to rotate with angular velocity `'omega'` in time 't' ?

Options

A. `(MRomega)/(4t)`
B. `(MRomega)/(2t)`
C. `(MRomega)/(t)`
D. `MRomegat`

Answer

B

Explanation

Given, mass of disc = M
Radius of disc =R
We know that, `tau=lalpha` . . . (i)
But `tau=FxxR`
`:." "l=(MR^(2))/(2)`
and `alpha=(omega)/(t)`
Therefore, `FxxR=(MR^(2))/(2)xx(omega)/(t)`
`F=(MR)/(2)xx(omega)/(t)" "F=(MRomega)/(2t)`