Question

$\begin{array}{cccc}& \text{Column I}& & \text{Column II}\\ \text{(i)}& \text{If friction force is less than}& \text{(a)}& \text{Static}\\ & \text{applied force then friction may be}& & \\ \text{(ii)}& \text{If friction force is equal to the}& \text{(b)}& \text{Kinetic}\\ & \text{force applied, then friction may}& & \\ & \text{be}& & \\ \text{(iii)}& \text{If object is moving, then friction}& \text{(c)}& \text{Limiting}\\ & \text{may be}& & \\ \text{(iv)}& \text{If object is at rest, then friction}& \text{(d)}& \text{No conclusion}\\ & \text{may be}& & \text{can be drawn}\end{array}$

• A. i - b; ii - a, b, c; iii - b; iv - a, b, c
• B. i - b; ii - a, c; iii - b; iv - a, c
• C. i - b; ii - a, b; iii - b; iv - a, b
• D. i - d; ii - a, b, c; iii - d; iv - a, b, c

Answer 1

The correct option is B i - b; ii - a, c; iii - b; iv - a, c

i → b; ii → a, c; iii → b; iv → a, c
For (i) and (iii): If $F>f$ it means object is moving and friction is kinetic in nature.
For (ii) and (iv): If $F=f$, then object is at rest and friction is static in nature. Another possibility is that $F=f_L$.