A horizontal plane supports a plank with a bar of mass m 1 0

Last updated: 6/10/2023

A horizontal plane supports a plank with a bar of mass m 1 0 kg placed on it and attached by a light elastic non deformed cord of length 1 40 cm to a point O Figure The coefficient of friction between the bar and the plank and elastic constant of cord both equal k 0 20 The plank is slowly shifted to the right until the bar starts sliding over it It occurs at the moment when the cord deviates from the vertical by an angle 0 30 Find the work in jouls that has been performed by that moment by the friction force acting on the bar in the reference frame fixed to the plane m lo