Q: The earth ( mass = 6 × 1024 kg) revolves round the sun with angular velocity 2×10-7 rad/s in a circular orbit of radius 1.5 × 108 km, the force exerted by the sun on the earth in newtons, is
(a) 18 × 1025
(b) Zero
(c) 27 × 1039
(d) 36 × 1021
Ans: (d)