Spinning Way Out Of Control (Angular Energy and Momentum HW)
1. A string is taped to a pool ball and wrapped tightly around. The ball
has a mass of 0.2 kg and a radius of 0.2m. The ball is released from rest
and rotates on the string as it descends. It descends down 0.5m comes to
a stop (so our toes hope). The thickness of the mass of the string and
thickness are negligible. A) What is the linear velocity as the pool ball
reaches 0.5m down? B) What is the tension on your finger as it reaches
the stop at 0.5m? C) What is the angular velocity as the pool ball reaches
0.5m D) What force should the tape be able to withstand (in N) If the time to bring the pool ball to
rest is 0.15s.
2. Calculate the angular momentum of a Compact Disc (CD) rotating at 331/3 rev/min. The CD has a
radius of 15 cm and a mass of 15.0 g. A typical CD can accelerate from rest to its final speed in 0.35
s, what average torque would be exerted on the CD?
3. A hamster running in an exercise wheel. Typical hamsters are 30.0 g and can
run at speeds of 3.2 m/s. A typical exercise wheel has a mass of 36.0g and behave
rotationally like a hoop. The radius of the wheel is 12.0 cm. A) Prove the linear
(p=m𝑣𝑡𝑎𝑛 ) and angular momentum (L=I𝜔) are equal (solve for both.) B) what is the
 of the wheel?
4. A) Determine the linear velocity (VT) of a 10-kg a hoop, disk and a
sphere of radius 20m, from rest on a 30deg incline of 200m.
b) What are their angular velocities at the bottom?