Question

A system of two masses, $m$ and $M$, and a pulley attached to table as shown in the diagram. What is the minimum value for the coefficient of static friction between mass $M$ and the table if the pulley system does not move?

• A. $m/M$
• B. $M/m$
• C. $g\left(m/M\right)$
• D. $g\left(M/m\right)$
• E. $g\left(M-m\right)$

Answer 1

The correct option is A $m/M$

Let the tension in the string be $T$.

For block of mass m : $T=mg$

For block of mass M : $T=f=\mu Mg$

$\therefore$ $mg=\mu Mg$

$⟹\mu =\frac{m}{M}$