Question

The schematic of an external drum rotating clockwise engaging with a short show is shown in the figure. The shoe is mounted at point Y on a rigid lever XYZ hinged at point X. A force F= 100 N is applied at the free end of the lever as shown. Given that the coefficient of friction between the shoe and the drum is 0.3, the braking torque (in Nm) applied on the drum is(correct to two decimal places)

• A. 8.18

Answer 1

The correct option is A 8.18

$\sum M_x=0$

$F\times 300+f\times 300=R_N\times 200$

$100\times 300+\mu R_N\times 300=R_N\times 200$

$100\times 300+0.3\times R_N\times 300=R_N\times 200$

$300=1.1R_N{R}_N=272.72N$

Braking torque =

= $\mu R_N\times R=0.3\times 272.72\times 0.100$

$T=8.18Nm$