Question

Consider the disc kept on a rough horizontal surface as shown in the diagram. If a horizontal force ‘F’ has to be applied such that the disc starts pure rolling. What should be the

• A. R
• B. $\frac{R}{3}$
• C. $\frac{R}{2}$
• D. Body can’t start pure rolling for any value of ‘h’

Answer 1

The correct option is C

$\frac{R}{2}$

For pure rolling
$a_{CM}=Rh\frac{F}{m}=\frac{R.F(h+R)}{3\frac{m{R}^2}{2}}$
On solving, $h=\frac{R}{2}$