Question

In the figure, a block of weight $60N$ is placed on a rough surface. The coefficient of friction between the block and the surface is $0.5$. What should be the weight $W$ such that the block does not slip on the surface?

Answer 1

Since, block does not slip, hence, $T_1<f_{max}$

$⟹T_1<\mu mg$

Now, for equilibrium-

$\frac{T_1}{\sin {135}^o}=\frac{T_2}{\sin {90}^o}=\frac{W}{\sin {135}^o}$

$⟹T_1=W$

$⟹W<\mu mg=0.5\times 60\times 9.8$

$⟹W<294N=30kg-wt$ for block does not slip.