<span>Answer:
Yes, I get 17 rad/s², too.
Note that the assumption of constant angular acceleration is really, really, terrible. A valid answer to this question (i.e., one that does not assume constant angular acceleration) involves differential equations. But if you do assume constant angular acceleration, this is quite straightforward. Use constant-acceleration kinematics:
Δθ = ω_i Δt + ½α (Δt)²
You know the pencil moves through an angle of π/2 radians. The initial angular velocity is zero. You already found the angular acceleration, and you want Δt.
Δt = âš[ 2 Δθ / α ] = âš[ 2 (Ď€/2 rad) / 17 rad/s² ] = 0.34 s
This is the same calculation oldprof makes, but his treatment of the pencil as a point mass rather than a uniform rod has thrown his angular acceleration off.</span>
The volume of a cube is given by:
where L is the measure of each side (which corresponds to its width, since all sides of a cube are equal).
Plugging the data of the problem, L=32.1 cm, inside the equation, we find the volume:
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Rrrrdndndndjdjdjdjjdjdjdjdkdmdmdmdkdjdjdjdjdid
Are breathing hard. This is because cardiovascular exercise makes the heart beat faster which in turn creates a need for more air.
True they only move in back n forth motion