Question

If a force of $5N$ is applied on a block of mass $10kg$ and the block remains at rest. then the magnitude and the direction of friction is

• A. $10N$ normal to the direction of motion
• B. $5N$ along the direction of applied force
• C. $5N$ opposite to the direction of applied force
• D. $10N$ opposite to the direction of applied force

Answer 1

The correct option is C $5N$ opposite to the direction of applied force

When we are applying a certain force on an object and still it is at rest then who is stopping it from moving, its Friction. And the friction which resists it from moving from its rest state is called Static friction. Since static friction is self adjusting friction and is equal to the force applied but in the opposite direction. So here $5N$ force was applied so static friction resists it with a magnitude of $5N$ in opposite direction.

For keeping the object to be at rest, forces acting should be balanced,
so Net force=0
For this Friction force should be 5N(in opposite direction to the applied force)