A merry-go-round (I = 1000 kg m²) rotates at 0.5 rad/s. A 50 kg child runs and jumps onto it at radius 2 m. New angular velocity (assume child becomes part of the system):
ACannot determine
B0.25 rad/s
C0.42 rad/s
D0.5 rad/s
Answer & Solution
Correct answer: C. 0.42 rad/s
Use angular momentum conservation. Before: L = 1000 × 0.5 = 500 kg m²/s. After: I_new = 1000 + 50 × 4 = 1200. omega_new = 500/1200 ≈ 0.417 ≈ 0.42 rad/s.
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