A plank is held at an angle `alpha` to the horizontal on two fixed supports A and B. The plank can
Channel: Doubtnut
Date: 2020-07-26

A plank is held at an angle `alpha` to the horizontal on two fixed supports A and B. The plank can slide against the supports (without friction) because of the weight Mg `sin alpha`. The acceleration and direction in which a man of mass m should move so that the plank does not move are