Question

A stone is attached to one end of a string. A child whirls the stone at a constant speed in a horizontal circle with a radius of 0.5 m. The stone makes 5 revolutions in 4 s

Answer 1

Find the tension of the string. Assume that the mass of the stone is 1 $kg$ . So, we have

$F=m\frac{v^2}{r}=m\cdot\frac{(5\cdot2\cdot\pi\cdot r/4)^2}{r}=m\cdot6.25 \cdot\pi\cdot r=$

$=1\cdot6.25\cdot3.14\cdot0.5=9.82(N).$ Answer