A pottery wheel with a mass of 10 kg and radius of 0.2 m is spinning at a rate of 3 rev/s (the wheel can be treated as a solid disk). A stray ball of clay flies at a speed of 21 m/s along a path tangent to the edge of the wheel and sticks to it, such that the wheel’s rate of spin slows to 1.5 rev/s. What is the mass of the ball of clay?
