Physics 122 2/4/11 Prof. E. F. Redish 1 2/4/11 1 Physics 122 2/4/11 9 Physics 122 a =Fnetma = kxm= 02x102d2xdt2= x= 0t1 02d2xdt2= x d2xd2= xx = Asin+ Bcosx = Asin 0t + Bcos 0t2/4/11 10 Physics 122 R x y x = Rcosy = Rsin=0tPhysics 122 2/4/11 Prof. E. F. Redish 2 2/4/11 11 Physics 122 2/4/11 12 Physics 122 FS MFE Ma =1mFnetFnet= kxa = 02x02=kmx(t) = Acos(0t )0=2 TMeasured from where? Interpret! 2/4/11 13 Physics 122Physics 122 2/4/11 Prof. E. F. Redish 3 2/4/11 15 Physics 122 221mvKE =rFnet=Work ()rFmvnet= 2212/4/11 16 Physics 122 Ug= mgh Uspr=12k l()22/4/11 17 Physics 122 12mvi2+U(ri) =12mvf2+U(rf)12mv2+U()= 012mv2+U()=Fnon consnet rPhysics 122 2/4/11 Prof. E. F. Redish 4 2/4/11 18 Physics 122 FS MFE ME =12mv2+ mgh +12k l()2Ei= EfMeasured from where? 2/4/11 23 Physics 122 2/4/11 28 Physics 122 a =1mFnet=1mT + mg()Fxnet= T sinFynet= T cos mgVery little up and down motion. Mostly left and right. The angle stays very small – a few degrees (<0.16 radians)Physics 122 2/4/11 Prof. E. F. Redish 5 2/4/11 29 Physics 122 2/4/11 30 Physics 122 a =1mFnet=1mT + mg()Fxnet= T sinFynet= T cos mgVery little up and down motion. Mostly left and right. ax= 1mT sin= TmxLay 0 =1mT cos mg()T mgax= gLx2/4/11 31 Physics 122 ax= gLxax= 02x02=gLSame as mass on a spring! Just with a different 0. What’s the period? Why doesn’t it depend on
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