Two cannons of mass 100 kg are placed on a uniform disc of radius 4.0 m and mass 400 kg. one cannon is located at the edge of the disc and the other cannon is placed on the opposite side of the disc half way between the center of the disc and the edge. the two cannons fire simultaneously in the same direction (toward the left). the cannonballs each have a mass of 2.0 kg and are moving at 250 m/s.

a. what is the angular velocity of the disc after the cannons are fired? is it rotating clockwise or counterclockwise?

b. suppose we could stop the rotation of the disc by firing a third cannonball. which cannon must fire and how fast must the cannonball be moving?