Question

Two bodies A and B, of different materials are kept on a horizontal surface. A graph of limiting friction (F) versus normal force (N) is as shown. Which one has a smoother surface in contact with the plane?

• A. A
• B. B
• C. Both A & B
• D. Neither ‘A’ nor ‘B’

Answer 1

The correct option is B

B

As $\mu =\frac{F}{N}$ = slope of F – N curve, which is greater for ‘A’.

$\therefore$ Force of friction for body A is larger

$\Rightarrow$ Surface of ‘B’ in contact with the plane must be smoother.