On a separate piece of paper, answer the following questions. Turn in on Monday, February 7.

1. What is a lever arm?

A lever arm is the distance from the point of the applied force to the axis.

2. A person pushes a door open by applying a force perpendicular to the lever-arm at a distance of 0.25 m from the hinges.

a. Draw a picture of this situation. In your picture, be sure to identify the lever arm.

b. If the person pushed with a force of 3.0 N, find the torque produced by this push.

c. How much torque would the person have generated if they applied the force at an angle of 60.0°, rather than perpendicular (90°).

3. If the torque required to loosen a nut on the wheel of a car has a magnitude of 40.0 Nm, what minimum force must be exerted by a mechanic at the end of a 30.0 cm wrench to loosen the nut?

4. A simple pendulum consists of a 3.0 kg point mass hanging at the end of a 2.0 m long light string that is connected to a pivot point.

a. Draw a picture of this situation. In your picture, be sure to identify the lever arm and the pivot point.

b. Calculate the magnitude of the torque (due to the force of gravity) around this pivot point when the string makes a 5.0° angle with the vertical.