Physics- Angular Velocity?

Question

A gymnast is performing a floor routine. In a tumbling run she spins through the air, increasing her angular velocity from 3.00 to 4.15 rev/s while rotating through one-third of a revolution. How much time does this maneuver take?

Answer 1

on rev/s = 6.28 rad/s

w=wi+α*t
th=thi+wi*t+.5*α*t^2

7.22=α*t
2.09=18.84*t+.5*α*t^2

2.09=18.84*t+.5*7.22*t

t=2.09/(18.84+.5*7.22)
t=0.0931 seconds

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