## Impulse Momentum Method for Rotational

M1=Iω
=0

M2=Iω
=(2.5)(V/0.15)
=16.67V

I1-2= Torque x Time
=(TaX0.075-75X0.15)5
=17.325-1.5V

M1+I1-2=M2
17.325-1.5v=16.67v
17.325=18.17v
v=0.95

v=rω
0.95=0.15ω
ω=6.3 wrong again

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 Quote by freshbox M2=Iω =(2.5)(V/0.15) =16.67V
Same problem with radius vs diameter. (Sorry I didn't spot it before.)

 how come i need to take the radius of the axle and not the wheel?

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 Quote by freshbox how come i need to take the radius of the axle and not the wheel?
You are relating ω to the speed V, which is the tangential speed of the axle edge, not the wheel edge.

 Can I say the "v" that I am finding is actually the velocity of the axle. After getting the velocity of the axle, I divide by 0.075 (axle radius) is because in a compound pulley, Angular velocity are the same. I am just using the axle velocity to get ω.

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 Quote by freshbox Can I say the "v" that I am finding is actually the velocity of the axle. After getting the velocity of the axle, I divide by 0.075 (axle radius) is because in a compound pulley, Angular velocity are the same. I am just using the axle velocity to get ω.
Yes. V is the velocity of the falling mass, and since its cord is wrapped around the axle, V is also the tangential velocity of the axle.

The axle and wheel are attached, so they have a common ω.

 Ok..I'm sorry can you help me take a look at this question part C M1=Iω =(3.5)(12.5) =43.75 M2 =Iω =3.5ω I1-2=Torque X Time =[(-TA)(0.2)+(TB)(0.5)]5 =-32ω+3783.5 M1+I1-2=M2 43.75-32ω+3783.5=3.5ω 3827.25=35.5ω ω=107.80 - Wrong Answer Attached Thumbnails

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 Quote by freshbox M1=Iω =(3.5)(12.5) =43.75 M2 =Iω =3.5ω I1-2=Torque X Time =[(-TA)(0.2)+(TB)(0.5)]5 =-32ω+3783.5
Double check that last calculation.

 =[(-TA)(0.2)+(TB)(0.5)]5 =[(-2ω+465.5)0.2+(1327.2-12ω)0.5]5 =(-0.4ω+93.1+663.6-6ω)5 =(-6.4ω+756.7)5 =-32ω+3783.5 I'm abit blind hehe can you tell me where is wrong?

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 Quote by freshbox =[(-TA)(0.2)+(TB)(0.5)]5 =[(-2ω+465.5)0.2+(1327.2-12ω)0.5]5
Looks to me like you left out a minus sign.

 fail -.- what a mess...hehe anyway thanks for your time and help (voko too), thanks :)
 I can't believe I mistook the diameters for the radii, but I did. Not just once, but multiple times when I cross-checked my results via at least three different methods. Oh well. Thanks Doc Al for pointing that out.