Finding a max angular acceleration

AI Thread Summary
To find the maximum angular velocity and corresponding angular acceleration of a 6' long, 40 lb bar released from a horizontal position, one must analyze the system using the moment of inertia about the pivot point O and apply the equation for torque. The sum of the torques about point O equals the moment of inertia multiplied by angular acceleration (Iα). The relationship between angular acceleration and angular velocity can be expressed as a(t) = r*α. The discussion emphasizes the importance of understanding the dynamics of rotational motion and the role of net torque in determining angular velocity. Proper application of these principles will lead to the desired values for maximum angular velocity and acceleration.
jhayes25
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Given is a 6' long 40 lb bar hung horizontally by a pin O at its end. It is released from its horizontal position and hits a stopper after reaching a 30 degree angle with the horizontal position at which it started. I am asked to find the value x for which the angular velocity is a maximum and also the corresponding angular acceleration alpha


Sum of the torques about O=I(alpha)
a(t)=r*alpha


I honestly do not know where to start with this one. do I start by summing moments about O?
Thanks in advance for any help.
 
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jhayes25 said:
Given is a 6' long 40 lb bar hung horizontally by a pin O at its end. It is released from its horizontal position and hits a stopper after reaching a 30 degree angle with the horizontal position at which it started. I am asked to find the value x for which the angular velocity is a maximum and also the corresponding angular acceleration alpha

Hi jhayes25! :smile:

(what's x? :confused:)

Hint: use the moment of inertia of the bar about its end, and net torque = rate of change of angular momentum. :wink:
 

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