Question

A simple pendulum is set up in a trolley which moves to the right with an acceleration 'a 'on a horizontal plane. Then the thread of the pendulum in the mean position makes an angle θ with the vertical

Answer 1

Explanation:

Due to horizontal acceleration, a pseudo force ma acts on the bob of pendulum in horizontal direction, backwards. Also the gravitational force mg acts on it vertically downwards.

Hence the angle that the thread makes with the vertical =tan−1(FyFx) =tan−1(mgma) =tan−1(ga) in backward direction