Physics [1 Mark Question Answer]

The SI unit of centripetal force is newton (N).

Centripetal force : The force acting on a body moving in a circular path. It acts along the radius of the circle and towards its centre.

When a particle moves with a constant speed in a circular path, its motion is said to be the uniform circular motion.

Centrifugal force acts away from the centre of circular path.

Centripetal force has a reaction force in accordance with the Newton's third law of motion. This oppositely directed force is called centrifugal force.

No, the earth moves round the sun with a variable velocity. Since the direction of motion changes at each and every point the velocity becomes variable.

Torque

The moment of force is a vector quantity.

Principle of moments: If a body is in equilibrium under the action of number of force, then the sum of clockwise moments is equal to the sum of anticlockwise moments.

A long handle facilitates increased torque with small application of force; hence a spanner has a long handle.

Two equal and opposite parallel forces acting along different lines on a body constitute a couple.
Effect of couple : It produces angular acceleration.