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Mark617
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Homework Statement
How much work is required to accelerate a horizontal wheel of mass 1150 kg from rest to a rotational rate of 1 revolution in 5 seconds
Homework Equations
I = 1/2(m)(r^2)
Rotational KE (ie work) = KE2 - KE1
Rotational KE = (1/2)(I)(Omega Squared)
The Attempt at a Solution
Without a radius or diameter, I find it impossible to get a final answer. Furthermore, it is not stated whether or not the acceleration is uniform, therefore I don't know that I can use the kinematic equations since they rely on a constant acceleration. If acceleration was uniform the angular acceleration would be 0.251327 rad/s^2 but I am not sure how this helps me since it seems everything is dependent on a radius.
We do not use I = m(r^2) because our teacher made it clear the wheel is not a rigid object instead it is a solid cylinder, so we use the above equation for I.
We can derive a frequency of 0.2 rev/s, a period of 5 seconds for one revolution, and an Omega (angular velocity) of 0 rad/s initial, 1.25664 rad/s final.
I come to a final answer of work = 454 x (radius ^2).
Am I missing something? Can I go any further without more information?
This is a basic Physics I class. I am sure there is an answer that can be derived but if it requires some advanced formulas I am not sure I can give that answer as we may not have covered that material (yet).
Thank you for any help that can point me in the right direction / help me understand this question!
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