Centripetal force refers to the force that makes objects move in circular paths. Centripetal force makes an object or body follow a curved path; the direction of the body moves towards the center or fixed point of the circular path.
Depending on the way the force is applied, the path of the body or object in motion may be a slight curve, full circle or cone-like shape. Common examples of centripetal force include the motion of the moon around Earth, swinging a ball on a rope and a race car zooming around a curve.
Centripetal forces are always perpendicular to the motion of the object over a period of time. This relationship causes the object to move along a curved path.
Objects moving in a circular fashion experience acceleration even if moving around the perimeter of the circular shape with constant speed. This acceleration always pushes towards the center of the circle. According to Newton's first law of motion, moving objects naturally want to continue moving in the same direction unless an unbalanced force acts upon the object to knock it off its path. Moving objects naturally travel in straight lines until an unbalanced force requires it to turn or change directions. As a result, unbalanced forces are needed for objects to travel in circles.