In the diagram shown, the blocks A and B are of the same mass M and the mass of the block C is M 1 . Friction is present only under the block A . The whole system is suddenly released from the state of rest. The minimum coefficient of friction to keep the block A in the state of rest is equal to

Step-by-step solution

When extension in spring is maximum, then maximum spring force will act on block   A . In this situation required (calculated ) friction to keep block A at rest will be minimum Let x is maximum extension and at maximum extension kinetic energy of whole system is zero. By COME Gain in E.P.E. of spring = Loss in  G.P.E. of block C So, 1 2 kx 2 = M 1 gx x = 2 M 1 g k ......................(i) To keep block   A at rest kx ≤ μN kx ≤ &