Question

A cube of side $a$ and mass $m$ is to be tilted at a point $A$ by applying a force $F$ as shown in the figure. The minimum force required is (Given acceleration due to gravity $=g$)

• A. $mg$
• B. $\frac{2}{3}mg$
• C. $\frac{3}{2}mg$
• D. $\frac{3}{4}mg$

Answer 1

The correct option is B $\frac{2}{3}mg$

The minimum force at which the cube will tilt will be when the torques of the forces acting about A will be equal.
Thus we get $mg\left(\frac{a}{2}\right)=F\left(\frac{3}{4}a\right)$
Thus we get
$F=\frac{2}{3}mg$