A plank of mass M_(1)=8kg with a bar of mass M_(2)=2kg placed on its rough surface,lie on a smooth floor of elevator ascending with an acceleration g/4.The coefficient of friction is mu=1/5 between M_(1) and M_(2).A horizontal force F=30N is applied to the plank.Then the acceleration of bar and the plank in the reference frame of elevator are:

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

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 disc of mass m and radius R is placed over a plank of same mass m. There is sufficient friction between disc and plank to prevent slipping. A force F is applied at the centre of the disc. Acceleration of the plank is

A plank of mass 10 kg and a block of mass 2 kg are placed on a horizontal plane as shown in the figure. There is no friction between plane and plank. The coefficient of friction between block and plank is 0.5 .A force of 60 N is applied on plank horizontally. In first 2 s the work done by friction on the block is

A block of mass m=2kg of shown dimensions is placed on a plank of mass M = 6Kg which is placed on smooth horizontal plane. The coefficient of friction between the block and the plank is mu=1/3 . If a horizontal froce F is applied on the plank, then find the maximum value of F (in N) for which the block and the plank move together

A solid sphere of mass m and radius R is placed over a plank of same mass m . There is sufficient friction between sphere and plank to prevent slipping. When a horizontal force F is applied at centre of sphere, acceleration of the plank is

A block of mass m=2kg is placed in equilibrium on a moving plank accelerating with a=1m//s^(2) . If coefficient of friction between plank and block mu=0.2 . The friction force acting on theblock is:

A block of mass m=2kg is placed in equilibrium on a moving plank accelerating with a=4m//s^(2) . If coefficient of friction between plank and block mu=0.2 . The friction force acting on theblock is:

A plank of mass m_1 with a bar of mass m_2 placed on it lies on a smooth horizontal plane. A horizontal force growing with time t as F^'=at (a is constant) is applied to the bar. Find how the accelerations of the plank w_1 and of the bar w_2 depend on t, if the coefficient of friction between the plank and the bar is equal to k. Draw the approximate plots of these dependences.

A disc of mass m and radius R is placed over a plank of same mass m. There is sufficient friction between disc and plank to prevent slipping. A force F is applied at the centre of the disc. Force of friction between the disc and the plank is