Centripetal force

• If a body moves in a circular path with constant angular velocity,it has a constant linear velocity along the circumference of the circular path.When the body moves along the circle, the direction of velocity changes at every point on the circle. However,the magnitude of the velocity remains the same.The change in direction of the velocity of the particles moving in the circle implies that the particles has an acceleration.If a particle has an acceleration,a force must have acted upon it cause the acceleration.This implies that if a body is moving uniformly in a circle,a force is acting on the body at every point on the circle. The force acting on the body is such that, at every point, the force changes the direction of the velocity keeping the magnitude constant.This is possible only if the force acts perpendicular to the direction of the velocity.The direction of the velocity of the body at any point on the circle is tangent to the circle at the point.Thus,it is clear that the force acting on the body moving in a circle at a point is always perpendicular to the tangent to the circle at the point. This means that the force acting on the body moving in a circle is always along the radius and towards the centre of the circle is called centripetal force. The acceleration thus produced on the body due to the centripetal force is called centripetal acceleration.
• Thus, the centripetal force on a body is defined as the external force which causes the boy to move in a circular path with a constant velocity,and acts along the radius and towards the centre of the circular path.