Question

Read the following two statements and then identify the correct choice of the given answers.
A : The frictional force acting on a body of mass m which is at rest on a horizontal surface of coefficient of static friction ${}^{\prime }{\mu }_s^{\prime }$ is ${\mu }_{s}mg$ in the absence of external force.
B : The frictional force acting on a body of mass m which is at rest on a rough inclined surface of angle of inclination $\theta$ is mg sin $\theta$.

• A. A is true and B is false
• B. A is false and B is true
• C. Both A and B are true
• D. Both A and B are false

Answer 1

The correct option is B A is false and B is true

Explanation of statement A: The frictional force acting on a body which is at rest on a horizontal surface is zero since there is no external force acting on the body.
Explanation of statement B: When the body is on a rough inclined plane then two forces acting on the body are gravity and frictional force since body is at rest these two forces are equal.