Question

Two blocks each having mass of 20 kg rest on frictionless surfaces as shown in the Figure. Assume that the pulleys to be light and frictionless. Now, find (a) the time required for the block A to move 1 m down the plane, starting from rest and (b) the tension in the cord connecting the blocks.

Answer 1

For block A apply Newton’s second law of motion along the inclined and for block B apply Newton’s second law along the horizontal.

Both the blocks A and B are considered as two independent systems. The FBDs for the blocks A and B are shown in the Figure and

Figure where T is tension in the string.

Now, by adding equations (i) and (iii), we obtain