1. Ch. 12 slides

2. The fan
A spider makes its home on top of a ceiling fan a 1/2 meter from the center of the fan. Bill Nye turns on the fan. The fan takes 2 seconds to go from rest to its final angular speed of 120 revolutions per minute. Amazingly, the spider moves with the fan without slipping.
What is the final angular speed of the fan in SI units? What is the final speed of the spider?
What is the angular acceleration (assuming that it's constant) of the fan during the first 2 seconds? What is the acceleration of the spider after 1 second?
What is the angular displacement of the fan during the first 2 seconds? How far has the spider traveled?

3. Angular accelerometer
a (rad/s2)
An angular accelerometer is attached 0.25m from the center of a disc that can spin. 4 3 2 1
t (s) 1 2 3 4 5
Using the graph (not equations), find the angular velocity w at t = 1, 2, 3, 4, 5 s, assuming at t = 0 s, w = 0.
At t = 3 s, what is the tangential velocity, tangential acceleration, and the radial acceleration?
At t = 5 s, find the same quantities as part b)
Velocity.ppt

4. Torque

5. Moment of Inertia

6. Tom and Jerry
Tom and Jerry both push on a merry-go-round as shown. The merry-go-round has a radius of 0.5 m and moment of inertia of 4 kg-m2. Tom pushes with a force of 4 N and Jerry pushes with a force of 2 N. what is the angular displacement of the merry-go-round after 2 s?

7. Similar to Example 12.12: Time for a bucket to fall
A 2.5 kg bucket of water is raised up 4 m from the ground on a pulley with mass 3kg and with a diameter of 4 cm. How long does it take for the bucket to hit the ground after it is released from rest?

8. Stick on Two Scales
Two scales are placed on the ground 2 meters apart. A board is placed between the scales. Skylar (60 kg) stands a 1/2 meter from one of the scales. What will be the reading on each scale? Assume that the mass of the board is much less than the the mass of Skylar.

9. Ladder
A 3-m-long ladder leans against a frictionless wall at an angle of 60°. What is the minimum value of µs that prevents the ladder from slipping?

10. The Great Downhill Race
A sphere, a cylinder, and a circular hoop, all of mass M and radius R, are placed at a height h on a slope of angle . Which one will win the race to the bottom of the hill? What will be its speed?

11. The Great Downhill Race
A sphere, a cylinder, and a circular hoop, all of mass M and radius R, are placed at a height h on a slope of angle . Which one will win the race to the bottom of the hill? How long will it take the fastest object?