A bar of mass `m_(1)` is placed on a plank of mass `m_(2)` which rests on a smooth horizontal plane . The coefficient of friction between the surfaces of bar and plank is k . The plank is subjected to a horizontal force F depending on time t as F = at , where a is a constant . The moment of time `t_(0)` at which the plank starts sliding is :

A bolck of mass m =2 kg is placed on a plank of mass M = 10 kg, which is placed on a smooth horizontal plane as shown in the figure. The coefficient of friction between the block and the plank is mu=(1)/(3) . If a horizontal force F is applied on the plank, then the maximum value of F for which the block and the plank move together is (g=10m//s^(2))

A bolck of mass m =2 kg is placed on a plank of mass M = 10 kg, which is placed on a smooth horizontal plane as shown in the figure. The coefficient of friction between the block and the plank is mu=(1)/(3) . If a horizontal force F is applied on the plank, then the maximum value of F for which the block and the plank move together is (g=10m//s^(2))

Block A of mass m rests on the plank B of mass 3m which is free to slide on a frictionless horizontal surface. The coefficient of friction between the block and plank is 0.2. If a horizontal force of magnitude 2 mg is applied to the plank B. The acceleration of A relative to the plank is ng/5 where n is.

A man of mass m is standing on a plank of equal mass m resting on a smooth horizontal surface. The man starts moving on the plank with speed u relative to the plank. The speed of the man relative to the ground is

A man of mass m is standing on a plank of equal mass m resting on a smooth horizontal surface. The man starts moving on the plank with speed u relative to the plank. The speed of the man relative to the ground is

Block of mass m rests on the plank B of mass 3m which is free to slide on a frictionless horizontal surface. The coefficient of friction between the block and plank is 0.2. If a horizontal force of magnitude 2 mg is applied to the plank B, the acceleration of A relative to the plank and relative to the ground respectively, are