The block brake consists of a pin-connected lever and friction block at $B$. The coefficient of static friction between the wheel and the lever is $\mu_{x}=0.3,$ and a torque of $5 \mathrm{N} \cdot \mathrm{m}$ is applied to the wheel. Determine if the brake can hold the whecl stationary when the force applicd to the lever is
(a) $P=30 \mathrm{N},$ (b) $P=70 \mathrm{N}$.