Pulley and torque

Homework Pulley

Answers

1. The torque exerted by the force F1 is

T1 = F1 x R1 = F1*R1*sin(90) = 21*0.4 = 8.4 N*m  , the direction is out of the page

2. The torque exerted by the force F2 is

T2 = F2 x R2 = F2*R2*sin(90) =5*1.3 =6.5 N*m,   the direction is out of the page
(T1 and T2 have the same sense because F1 is applied on the left side of the pulley and F2 is applied on the right side of the pulley)

3. Since F3 is balancing F1 and F2 (and not the torques T1 and T2) we can write

F3 = F1 – F2 =21-5 =16 N

4. The torque exerted by F3 is

T3 = F3 x R3 = F3*R3*sin(90) = 16*1.5 = 24, the direction is into the page