Question

A block of mass m is attached with a massless spring of force constant k. The block is placed over a rough inclined surface for which the coefficient of friction is 0.5. M is released from rest when the spring was unstretched. The minimum value of M required to move the block m up the plane is (neglect mass of string and pulley and friction in pulley)

• A. m/2
• B. m/3
• C. m/4
• D. m

Answer 1

The correct option is D m

$\begin{array}{c}Mg=mg\sin {37}^0+\mu mg\cos {37}^0\\ \Rightarrow M=m\times \frac{3}{5}+0.5\times m\times \frac{4}{5}\\ =\frac{3}{5}+\frac{2m}{5}=m\\ Hence,\\ optionDiscorrectanswer.\end{array}$