Question

Block A of weight 100 kg rests on a block B and is tied with horizontal string to the wall at C. Block B is of 200 kg. The coefficient of friction between A and B is 0.25 and that between B and surface is $\frac { 1 } { 3 }$ . The horizontal force F necessary to move the block B should be (g = 10 m/s²) –

• A. 1050 N
• B. 1450 N
• C. 1050 N
• D. 1250 N

Answer 1

Answer: (D)

1250 N

Answer 2

F = µ₁mg + µ₂ (M + m)g

= 0.25 (100) (10) + $\frac { 1 } { 3 }$ (300) (10) = 1250 N