A space station is constructed in the shape of a hollow ring ofmass 4.80 104 kg. Members of the crew walk on a deckformed by the inner surface of the outer cylindrical wall of thering, with radius 105 m. At rest whenconstructed, the ring is set rotating about its axis so that thepeople inside experience an effective free-fall acceleration equalto g. (The figure below shows the ring together with someother parts that make a negligible contribution to the total momentof inertia.) The rotation is achieved by firing two small rocketsattached tangentially to opposite points on the outside of thering.
(a) What angular momentum does the space station acquire?

(b) How long must the rockets be fired if each exerts a thrust of125 N?