Q. A rectangular block has a square base measuring $a \times a$, and its height is $h$. Its moves on a horizontal surface in a direction perpendicular to one of its edges. The coefficient of friction is $\mu$. It will topple if
A) $\mu > h/a$
B) $\mu > a/h$
C) $\mu > \frac{2a}{h}$
D) $\mu > \frac{a}{2h}$
Explanation
(b) As shown in figure normal reaction $R = mg$. Frictional force $F = \mu R = \mu\ mg$. To topple, clockwise moment must be more than the anticlockwise moment $ie,\ \mu mg \times \frac{h}{2} > mg \times \frac{a}{2}mg \times \frac{a}{2}\ or\ \mu > a/h$
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Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.