Physics - Rotation Question with Solution | TestHub

Block is not moving, so friction f = F

At the point of toppling, N = mg acts at the right edge, a/2 from the centre

Torque about the centre of the block:

$F\cdot \frac{a}{3}+f\cdot a=N\cdot \frac{a}{2}$

$F\left(\frac{a}{3}+a\right)=\frac{mga}{2}$

$\frac{4F}{3}=\frac{mg}{2}$

$F=\frac{3mg}{8}$

Answer: D