- #1

OrlandoLewis

- 25

- 1

## Homework Statement

Starting from rest, a wheel has constant α = 3.0 rad/s

^{2}. During a certain 4.0 s interval, it turns through 120 rad. How much time did it take to reach that 4.0 s interval?

ω

_{0}= 0

α = 3.0 rad/s

^{2}

θ

_{f}= 120 rad

## Homework Equations

Δθ = ω

_{0}⋅t + ½αt

^{2}

## The Attempt at a Solution

120 rad = (1/2)(3.0 rad/s

^{2})(t

^{2})

Solving for t:

t = [2(120 rad) / (3.0 rad/s^2)]

^{½}

t = 8.49 s

Subtracting 4.0 s to the said time leads to my final answer, 4.9 s

The book says that the answer should be 8.0 s.