Question

Two blocks A and B are pressed against a vertical wall by applying a horizontal force $F$. There is no friction between A and B. There is friction between block A and the wall. Then
a. Both blocks A and B can be at rest for any magnitude of $F$.
b. B can be at rest and A moves down for smaller magnitude of $F$.
c. Both A and B will move down for smaller magnitude of $F$.
d. A can be at rest and B moves down for larger magnitude of $F$.

• A. a & b are correct
• B. c & d are correct
• C. a & d are correct
• D. b & c are correct

Answer 1

The correct option is B c & d are correct

Since, there is no friction between body A and B, body B slides over A due to its weight. But there is a frictional force acting between A and wall, Thus, Body A avoids sliding because of friction.
Hence, both A and B will move down for smaller magnitude of $F$ and A can be at rest and B moves down for larger magnitude of $F$.