Q: A car is moving in a circular horizontal track of radius 10 m with a constant speed of 10 m/s. a plumb bob is suspended from the roof of the car by a light rigid rod. The angle made by the rod with the vertical is (take , g = 10 m/s2)
(a) zero
(b) 30°
(c) 45°
(d) non-zero
Ans: (c) , (d)