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Preptopro
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Homework Statement
So I have a horizontal pulley positioned at the edge of table with a mass of .2kg hanging down from a height of .76meters, the other end of the string is attached to a wooden block of mass .25kg that when the .2kg weight is dropped the wooden block is pulled towards the pulley .8 meters at a velocity of .92m/s. Now I need to find the GPE, translational, and rotational energy of the system. The objective is to have all 3 types of energies in the system.
Homework Equations
GPE = mgh
Translational energy= .5mv^2
Rotational energy = .5Iw^2 ?
The Attempt at a Solution
GPE would just be (.2kg)(9.8m/s^2)(.76m) = 1.5 Joules right?
Translational energy = .5(.25kg)(.92m/s)= .11 Joules, this doesn't seem right I'm guessing I have to account for friction or something else? Any ideas?
And for Rotational energy I have no idea where to begin, I is .5MR^2 and then since w is (v/r) does that mean I could use .5(.5MR^2)(w^2) which is .25(MR^2)(v/r)^2 and then simplifying further it'd be .25(M)(v^2)? Am I on the right track?
Someone else I asked said that this does not even have rotational energy, so I'm very lost and I'd greatly appreciate any input! Thank you very much!