A space station is constructed in the shape of a hollow ring of
mass 6×10^4 kg and radius 100 m. At rest when constructed, the ring
is set rotating about its axis at an angular speed of 0.3 rad/s so
that the people inside experience an effective free-fall
acceleration equal to g. The rotation is achieved by firing two
thrusters attached tangentially to opposite points on the rim of
the ring. If both thrusters had to be fired continuously (and
uniformly) for 12 hrs. to achieve the desired rotation, the
approximate thrust force exerted by each thruster is 21N, how?