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pb23me
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Homework Statement
A hoop rolling on a horizontal surface with a speed v=3.3m/s when it reaches a 15 deg incline.How far up the incline does it go?How long will it be on the incline before it reaches the botttom?
Homework Equations
I=mr2
conservation energy going up=2gyf=r2+vi2
conservation energy going down=2gyi=r[itex]\omega[/itex]2+v2
yf=sin(15)
circumference=2r[itex]\pi[/itex]=8.5m
The Attempt at a Solution
i used the conservation of energy equation and solved for r getting r=1.36m. I had my calculator in radian mode not sure what mode i should have had it in. Then i plugged the radius back in and got yf=.65m , sin(15) was also .65m so hypotenuse =1m. Then i used conservation of energy down equation and solved for [iex]\omega[/itex] getting [itex]\omega[/itex]=2rad/s i found how many radians the hoop went through by noting that the hypotenuse was 1m long so 1/8.5(2[itex]\pi[/itex])=.74 radso [itex]\omega[/itex]=.74rad/t=.37s