1. The problem statement, all variables and given/known data A wheel rotates with a constant angular acceleration of π rad/s^2. During a certain time interval its angular displacement is π rad. At the end of the interval its angular velocity is 2π rad/s. What is its angular velocity at the beginning of the time interval? 2. Relevant equations angle displacement = (initial rotational velocity * time) + 1/2(rotational acceleration)time^2 rotational velocity = rotational acceleration * time rotational velocity^2 = (initial rot. velocity^2) + 2(rotational acceleration)(angle displacement) 3. The attempt at a solution When plugging in the values into the third equation, I'm able to solve the problem and get the correct answer (π*sqrt2). But I'm wondering what's wrong with my other way of doing it. I tried solving for the time by plugging in the final velocity and acceleration into the 2nd equation (2π = π*t), which gives t = 2. Then I plugged the values into the first equation to try to solve for the initial angular velocity (π = (initial rotational velocity x 2) + 1/2(π)2^2 But that didn't work out. Is there a reason why? Thanks for any help!