Question

Match the block diagrams of block of mass, m, with their corresponding free body diagram.

(Bodies are at rest with respect to ground)

• A. P - (i); Q - (iii); R - (iv); S - (ii)
• B. P - (ii); Q - (ii); R - (iv); S - (ii)
• C. P - (i); Q - (iii); R - (iv); S - (iv)
• D. None of these

Answer 1

The correct option is B

P - (ii); Q - (ii); R - (iv); S - (ii)

Only forces are gravity and normal force applied by the ground on the block

Same as above as the block is at rest and there is no horizontal force applied on it and friction opposes relative motion

In this case, block b also applies a normal force $N_b$ on m in the downward direction

(S) The last case is again equivalent to the first case.