Question

A block is placed on a rough floor and a horizontal force $F$ is applied on it. The force of friction $f$ by the floor on the block is measured for different values of $F$ and a graph plotted between them ______
A. is a straight line of slope ${45}^0$
B. is a straight line of slope less than ${45}^0$
C. is a straight line of slope ${45}^0$ for small $F$ and a straight line parallel to the $F-axis$ for large $F$
D. there is a small kink on the graph

• A. B & D are correct
• B. A is correct
• C. C & D are correct
• D. A & B are correct

Answer 1

The correct option is C C & D are correct

For a small value of the applied force the force of friction f increases linearly upto the limiting friction. When it crosses the maximum point of static friction then the friction force due to kinetic friction does not change any more.