To throw a discus, the thrower holds it with a fully outstretched arm. Starting from rest, he begins to turn with a constant anguLar acceleration. The diameter of the circle in which the discus moves is about 1.8 m. If a thrower takes 1.0 s to complete one revolution, starting from rest, what will The speed of the discus be at release?(adsbygoogle = window.adsbygoogle || []).push({});

I'm just starting this question and am wondering why when I calculate the angular acceleration using formula:

Angular acceleration= change in Angular velocity/change in time which for this problem is 2pi rad/1 sec/1sec I get 2 pi rad/s^2

But when I use the formula:

Change in theta=initial angular velocity * initial change in time time + .5 * angular acceleration * time^2

I get 4pi rad/s^2 bc

2pi=.5(angular acceleration) (1)^2 I get 4pi rad/s^2. So why am I getting two different angular accelerations with these two formulas? I know the problem Is asking for speed but first I want to know why I get two different answers for angular acceleration.

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# Homework Help: Angular acceleration of a discus

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