AP Physics 1 / Unit 5: Torque and Rotational Dynamics
5.3 Torque
Notes
$$\tau=rF\sin\theta$$
- Torque is the rotational effect of a force; it's largest when the force is perpendicular to the lever arm.
- Counterclockwise is usually positive.
Practice
A 20 N force pushes perpendicular at 0.5 m from a hinge. Torque:
$0.5\times20$.
Why are door handles far from the hinge?
$\tau=rF$.
A force pointed straight at the pivot produces:
$\sin0=0$.
Ready for more? Take the Unit 5 test.