Question

On application of an external force on box A, the direction of frictional force on box A, applied by box B, would be:

• A. towards the applied force
• B. opposite to the direction of the applied force
• C. downwards
• D. upwards

Answer 1

The correct option is B opposite to the direction of the applied force

Due to the force on box A, it will have the tendency to move in the direction of applied force.
Since friction opposes relative motion. If A goes left, in the direction of applied force, then box B will apply a frictional force on it in the right direction, opposite to the direction of applied force.