A space station is constructed in the shape of a hollow ring of mass 5.00 104 kg. Members of the crew walk on a deck formed by the inner surface of the outer cylindrical wall of the ring, with radius 100 m. At rest when constructed, the ring is set rotating about its axis so that the people inside experience an effective free-fall acceleration equal to g. (Figure P11.27 shows the ring together with some other parts that make a negligible contribution to the total moment of inertia.) The rotation is achieved by firing two small rockets attached tangentially to opposite points on the outside of the ring.
(a) What angular momentum does the space station acquire?
(b) How long must the rockets be fired if each exerts a thrust of 125 N?
(c) Prove that the total torque on the ring, multiplied by the time interval found in part b), is equal to the change in angular momentum, found in part
(a). This equality represents the angular impulse–angular momentum theorem. |

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