a) suppose we tie a ball with a string and rotate it keeping its other end tied with one of our fingers then the only external force acting on it is the tension. Which force then cancells 'mg' acting vertically downward?
b) if a mass is rotating in a circular path then in which direction does the net external force acting on it acts?
262while we rotate the ball, the string is not completely horizontal.
actually at high velocities centripetal force(=mv2/r) becomes much much larger than mg
which is why string seems almost horizontal.
you can try this out,
first start rotating a ball with little velocity and slowly start increasing it.
the angle made by the string with the vertical will also gradually increase but will never reach 900.
thus one component of tension balances mg while the other supports the rotation.
36ya got it now..!!
thanks a lot
that means the only external force acting on the ball is the tension(T) acting towards the centre. Am i right?
7tension will have 2 components. the vertical one will balance the weight as Aditya pointed out.
1dats correct aditya
but certain amount of drag n intermolecular friction also contributes to d same
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