Question

A 43kg child stands on a spinning platform that has been well maintained(neglect friction in the axle). Initially the platform is spinning at 2.1 revs/s while the child's arms are extended outward(holding some weights). The child then pulls the weights back to close to their body. What is the final angular speed in revs/s of the platform? Assume that the child can be considered a cylinder with a diameter of 1.3m, spinning along its center axis and the weights are point masses (2kg each) that are initially 1.2m away from the center of the child. Assume that the weights are at the outer edge of the cylinder in the final moment.

Answer 1

Chiven Mass of child (M) diameler cylinden (R) -3 Radius 0.65 m 2 2 oeach weght (m) = 2 kg Mass = 1.2 m Drstemce of each weieht fram a xis 2.1 es Inital Spinning Spesol (i) = Soluhan: I child MR2 men ha of chi lol moment 드글x43 x (o6S) 2 9.083 Km Mo mont men hawejht we 2mr2 2x2 x (I-2) S.76 kam2 Using cansenvalamel anqulan momentum TenitoX (.083 S-76) (2.1) g.083 x u 3.4317 Teys

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