# Thread: Angular displacement

1. ## Angular displacement

The angular displacement, θ radians, of the spoke of a wheel is given by
the expression θ = 0.5t4 – t3, where t is time in seconds.
Find:
(a) The angular velocity after 2 seconds.

(b) The angular acceleration after 3 seconds.

(c) The time when the angular acceleration is zero.

2. ## Re: Angular displacement

Is that \displaystyle \begin{align*} \theta = 0.5t^4 - t^3 \end{align*}?

3. ## Re: Angular displacement

Find $\frac{d \theta}{dt}$ and $\frac{d^2 \theta}{dt^2}$ first.

4. ## Re: Angular displacement

yes it is sorry for the bad typing

5. ## Re: Angular displacement

Hint: Velocity is the derivative of displacement, and acceleration is the derivative of velocity (so the second derivative of displacement).