Chapter 9, Problem 28MCQ

A 4.0-m-diameter playground merry-go-round, with a moment of inertia of 400 kg · m², is freely rotating with an angular velocity of 2.0 rad/s. Ryan, whose mass is 80 kg, runs on the ground around the outer edge of the merry-go-round in the opposite direction to its rotation. Still moving, he jumps directly onto the rim of the merry-go-round, bringing it (and himself) to a halt. How fast was Ryan running when he jumped on?

A. 2.0 m/s

B. 4.0 m/s

C. 5.0 m/s

D. 7.5 m/s

E. 10 m/s