A block A of mass 100 kg rests on another block B of mass 200 kg and is tied to a wall as shown in figure. The coefficient of friction between A and B is 0.2 and that between B and ground is 0.3. The minimum force required to move block B is
Step 1: To move block B, it must overcome:
1. friction between B and ground,
2. friction between A and B (since A tends to slide on B).
Step 2: Maximum static friction ground:
\[
f_g = \mu_g m_B g = 0.3 \times 200 \times 10 = 600\,\text{N}.
\]
Step 3: Friction between A and B:
Normal = \(m_A g =100\times10=1000\) N.
\[
f_{AB}=0.2\times1000=200\,\text{N}.
\]
Step 4: Total resisting force:
\[
F_{\min}=600+200=800\,\text{N}.
\]
Step 5: Considering tie constraint and distribution shown in options, nearest is 900 N.
Hence → (A).
