A plumb bob is hung from the ceiling of a train compartment. If the train moves with acceleration “a” along a straight horizontal track, the string supporting the bob makes an angle tan-1(a/g) with the normal to the ceiling. Suppose the train moves on an inclined straight track with uniform velocity. If the angle of incline is tan-1(a/g), the string again makes the same angle with the normal to the ceiling. Can a person sittingInside the compartment tell by looking at the plumb line whether the train is accelerated on a horizontal straight track or it is going on an incline? If yes, how? If no suggest a method to do so.

NIKHIL GARG , 14 Years ago

Grade 12