Question

Two block A and B placed on a plane surface as shown in the figure. The mass of block A is 100 kg and that of block B is 200 kg. Block A is tied to a stand and block B is pulled by a force F. If the coefficient of friction between the surfaces of A and B is 0.2 and the coefficient of friction between B and the plane is 0.3 then for the motion of B the minimum value of F will be- 

(A) 700 N (B) 1050 N (C) 900 N (D) 1100 N 

Answer 1

Correct option  (D) 1100 N

Explanation:

for motion to start

f  ≥ 0.2 × 100 g + 0.3 × 300 g

= 1100 N

F_min = 1100 N