Question

If r=40cm, F= 150N, and the torque has maximum allowed value of 8.2 N.m the angle between the force and the lever arm should be equal to ____

Answer 1

By definition, the torque is the crossproduct of the force and the lever arm. Thus, its magnitude is given by:

$$\tau = rF\sin\theta$$

where $\theta$ is the angle between the force and the lever arm. Expressing $\theta$, obtain:

$$\theta = \arcsin\left( \dfrac{\tau}{Fr} \right) = \arcsin\left( \dfrac{8.2N\cdot m}{150N\cdot 0.4m} \right) \approx 7.86\degree$$

Answer. $7.86\degree$.