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    Let us consider a bob that is attached to a string and made to rotate on a circular path in the horizontal plane. Let us try to study the forces acting on the body. Let us see how the object is going to move in the circular path. In our previous article we have stated that the circular motion can be resolved into two orthogonal simple harmonic motions.

    Now we shall learn that in a more detailed manner. Notice that the velocity is always along the tangent to the circular path and the acceleration is towards the center of the path. Look at the two projections of the motion along the x- and y- directions. These two motions are simple harmonic in nature as the velocity is changing its direction at the extremities and the acceleration is changing its direction near the center. Also note that when the bob in the x- projection is at the end points corresponding to this in the y-projection it is at the middle of the path. which shows that these two motions are orthogonal or perpendicular to one another.

    Now let us see what happens when the bob is released at any point while in motion along the circular path. when the bob is released while in circular motion it goes in the direction of the tangent as the velocity is in that direction.

    Let us look at the above animation again. We have studied that accelerating bodies are subject to experience some or the other force. What is the force acting in this case then ?


    The force acting in this case is called the centripetal force. It is not a special type /kind of force, it is like any other force. We have used an adjective to describe the force to say that it is acting towards the center. Since the body is moving along a circular path there should be one more force countering the centrapetal force. we call this force as the centrifugal force. It is defined as the force, arising from the body's inertia, which appears to act on a body moving in a circular path and is directed away from the center around which the body is moving. In the present case these two forces are equal and opposite as a result the bob moves on the circular path.


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