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SherBear
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Homework Statement
Flywheels are large, massive wheels used to store energy. They can be spun up slowly, then the wheel's energy can be released quickly to accomplish a task that demands high power. An industrial flywheel has a 1.5 m diameter and a mass of 270 kg. Its maximum angular velocity is 1500 rpm. How much torque does the flywheel exert on the machine?
Homework Equations
to find Wf I used (1/2 K ) = 1/2 I wf ^ 2
then Wf=Wo+alpha(t)
then T for torque=I alpha
The Attempt at a Solution
to find Wf I used (1/2 K ) = 1/2 I wf ^ 2
=(1/2 (9.4*10^5 (this is what the amount of energy stored) = 1/2 (70.3125) <--This number is I=1/2mr^2 (wf^2)
I rearranged this to find Wf
Wf^2= .5(9.4*10^5) / .5 (70.3125)
wf= sqrt 470,000 / 35.15
= sqrt 13371.26
wf = 115.63
then i used wf=wo+alphat to find the angular acceleration
alpha=wf / wo + t
alpha=115.63 / 157 rad/s+2.1 s
alpha = .7267
then torque=I alpha
=70.3125 (.7267)
T=51.09 N*M
It was wrong and I have no idea what I'm doing wrong