Conical pendulum

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Two forces are acting on the mass m, one is the tension in the string and the other is its own weight. These two forces are combined to form a net force pointing towards the center of revolution. This net force is thus termed centripetal.

In this applet, you may set the length and the frequency either independent or correlated by the principle of conservation of angular momentum. The latter case happens, for example, when the length is shortened by pulling the string S down in the above diagram. The centripetal force is radially inwards, it does not produce a torque to spoil the (vertical) angular momentum. The value is a constant, so a reduction in r will speed up the mass simultaneously.

 

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