Practice problems

1. A disk is spinning at 12 radians per second, and comes to a stop in 26 seconds. Assume the angular acceleration is constant.

 

   A. What is the magnitude of the angular acceleration of the disk?

 

   B. How many revolutions does it make as it stops?

2. The angular velocity of a spinning disk is given by w(t) = A - B t2. A. At what time does the disk reverse direction? B. Through what angle does the disk turn between t = 0 and the time at which it reverses its direction of rotation? 3. Consider the system below: a bullet is shot through holes in two disks a distance D apart, attached to a shaft that rotates at constant angular speed with a period T. q describes the fixed angular separation of the holes. Derive a formula for the bullet speed v, in terms of given variables.

Check out the animation of this system by Behnam Saeedi.