Block A of mass m and block B of mass 2m are placed on a fixed triangular wedge by means of a light and inextensible string …

Q: Block A of mass m and block B of mass 2m are placed on a fixed triangular wedge by means of a light and inextensible string and a frictionless pulley as shown in figure. The wedge is inclined at 45° to the horizontal on both sides. The coefficient of friction between the block A and the wedge is 2/3 and that between the block B and the wedge is 1/3. If the system of A and B is released from rest, then the acceleration of A is

Numerical

(a) 1.5 ms-2

(b) 0

(c) 0.5 ms-2

(d) 1 ms-2

Ans: (b)

(fmax)A = μA(m g cos45)

(fmax)B = μB(2m g cos45)

Hence , the maximum value of friction obtained is

fmax = (fmax)A + (fmax)B …(i)

Net pulling force on the system is

F = F1-F2

F = 2m g sin45 – mg sin45 …(ii)

Pulling force < fmax

Therefore, the system will not move or the acceleration of block A will be zero.