Calculating Angular Velocity in a Centrifuge: Astronaut Test Problem

[Punchlinegirl]

An astronaut is being tested in a centrifuge. The centrifuge has a radius of 8.5 m and in starting, rotates according to theta= .21t^2, where t in seconds give theta in radians. When t=5.0 s, what are the astronaut's angular velocity?

I did .21(5.0)^2 / 5, to get angular velocity, but it was wrong. Can someone steer me in the right direction?

 

[whozum]

I have no idea what equation that is that your using.

$$\theta(t) = .21t^2$$

$$\omega(t) = .42t$$

by the relationship $$\omega(t) = d\theta(t)/dt$$

 

[dextercioby]

Why do they give the radius,if they don't ask for the tangential speed...?

Daniel.

 

[whozum]

Probably needs help on just one part of the problem.

 

[Punchlinegirl]

Ok I see what I was doing. Thanks so much