### Torque Sample Problems

1. An 8 N weight hangs at the end of a 4 m uniform board weighing 2 N. The board pivots at its center. How far must a 10 N weight be hung from the pivot to achieve equilibrium?
2. A 20 N force is applied at the end of a 4 m long massless pole. It is applied at an angle of 25. What torque is produced?
3. A tapered log 3 m long weighs 50 N and has its center of gravity 1 m from its thick end. It is supported at its center. Where must a 25 N weight be placed to establish equilibrium?
4. A 100 m long uniform bridge weighing 200 N is supported at each end by piers A and B. A 3500 N weight is 20 m from A and a 9000 N weight is 30 m from B. How much weight is supported by each pier?
5. Find the magnitude of the tension in the wire: It is a uniform bar weighing 12 N.

### Rotational Motion Sample Problems

1. A wheel spins at 400 rpm. What is its angular velocity in rad/s? If it has a radius of 10 cm, what is its tangential velocity?
2. Convert 400 rad/sec into a speed in rev/min. Assume the rotating object has a diameter of 10 cm, what is its tangential velocity?
3. A pulley with a diameter of 5 cm turns at 100 rad/s. Through what angular distance does it turn in 10 sec? Through what tangential distance? If it is stopped in 15 sec, what is its rate of angular acceleration? Tangential acceleration? Through what angular distance did it turn as it stopped? Through what tangential distance?
4. A wheel turning at 80 rad/s is brought to a stop in 10 sec. What is its rate of angular acceleration? Through what tangential distance did it turn?
5. A 5 N force is applied to a wheel with a moment of inertia of 0.080 kg m2 that has a radius of 5 cm. What angular acceleration did it cause?
6. A 10 N force is applied to a wheel with a radius of 3 cm causing an acceleration of 12 rad/s2. What is the moment of inertia of the wheel? Through what tangential distance did it turn in 5 seconds if it started from rest?