Question

An skater is able to spin at 4 rev/s.

What is her angular velocity in rad/s?

What is the centripetal acceleration of her arms if they are 0.85 meters from the axis of rotation?

Answer 1

here we have to apply this formula:
\[\omega = 2\pi f \cong 6.28 \cdot 4 = ...?\]
being \(f=4 \,s^{-1}\)

Answer 2

Where does the 6.28 came from?

Answer 3

I have used an approximated result, here is my step:
\[2\pi = 2 \cdot 3.14159... \cong 2 \cdot 3.14 = 6.28\]

Answer 4

Ok. thanks!