Q.

Two blocks (P and Q) with respectively masses 2 kg and 1.5 kg are joined by a massless thread. These blocks are mounted on a frictionless pulley which is fixed on the edge of a cube (S), as shown in the figure below. Block P is positioned on the top surface which has no friction and block Q is in contact with side-surface, having coefficient of friction μ. The cube (S) moves towards the right with acceleration of g2, where g is gravitational acceleration. During this movement the block P and Q remain stationary. The value of μ is ______.   (Take g = 10 m/s2)                      [2026]

1 0.33  
2 0.67  
3 1  
4 0.5  

Ans.

(2)

From F.B.D of 1.5 kg block:  f=μN2=μ×1.5g2        ...(i)

f+T=1.5g                                                                             ...(ii)

From F.B.D of 2 kg block:  T=2×g2                             ...(iii)

From (i), (ii) and (iii)

μ×1.5g2+2×g2=1.5g⇒μ=23