Common angular velocity Smile
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Posted by: daredvl

03/29/2006, 13:19:08

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Clutch: Plate A, mass 36kg, rad of gyration 0.12m and rotates at 660 rev/min ....... Plate B, mass 45kg, rad of gyration 0.16m and is stationary.
When plates are engaged, slipping ceases after 0.4 seconds then both rotate with a common angular velocity.

Calculate the common angular velocity after engagement?

My answer is -26.28 rad/sec Is this correct? Can the answer be a negative value? I also calculated torque to be 199.3Nm ???

Any advice please?

Cheers :-)








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Re: Common angular velocity
Re: Common angular velocity -- daredvl Post Reply Top of thread Forum
Posted by: swearingen

03/30/2006, 10:16:07

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I haven't done the numbers, but obviously that can't be correct. It can't start spinning the other way. And since your initial angular velocity is over 6000 rad/s and the flywheel you are speeding up is heavier and larger than the one doing the work, I expect the delta angular velocity to be greater than 26.28, although we know it well be negative, i.e. less angular velocity than what you started with.

Use the momentum equation to get your final angular velocity - pretty straightforward. From that you can get your energy loss. From that, coupled with the time of deceleration, you can get the torque required.








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Re: Common angular velocity
Re: Re: Common angular velocity -- swearingen Post Reply Top of thread Forum
Posted by: zekeman

03/31/2006, 00:33:28

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Try conserving angular momentum; time has nothing to do with it.
Is this homework? If it is, you have not learned the physics.
Pick up a book and read up on angular momentum and Newton's laws.
If you are a mechanical engineer or hope to be, you must know this in your sleep.







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Re: Common angular velocity
Re: Re: Common angular velocity -- zekeman Post Reply Top of thread Forum
Posted by: rfox71

04/10/2006, 11:44:46

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Using conservation of Angular Momentum to solve for the resultant speed and Impact/Momentum Principles to find the average applied force: (Units?? I just threw it together =\ Always check your units =)

Discs.GIF (8515 bytes)  





Modified by rfox71 at Mon, Apr 10, 2006, 11:50:18


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