Question

A 60-kg woman is on a large vertical swing of radius 20m. The swing rotates with constant speed.
a. At what speed would she feel weightless at the top?
b. At this speed, what is her apparent weight at the bottom?

Answer 1

$\left(a\right)$ To feel weightlessness,

$\frac{m{v}^2}{r}=mg\to \left(1\right)\therefore v=\sqrt{gr}=\sqrt{10\times 20}=14.14m/s$

$\left(b\right)W_{apparent}=mg+\frac{m{v}^2}{r}\to \left(2\right)\left(1\right)in\left(2\right)\Rightarrow W_{apparent}=2mg=120kg$