Question

A non uniform sphere can be kept on a rough inclined plane so that it is in equilibrium. In the figure below the dots represents location of centre of mass. In which one of the positions can sphere be in equilibrium?

• A. A
• B. B
• C. C
• D. D

Answer 1

Answer: (C)

C

For the sphere to be in equilibrium, $F_{Net}=0$ and ${\tau }_{Net}=0$

So, for point C: friction force will balance $mgsin\theta$

Now ${\tau }_o=mgcos\theta \times r-mgsin\theta \times d$

if $mgcos\theta \times r=mgsin\theta \times d$ then ${\tau }_o$ can be zero.