Physics 121 9/27/10 Prof. E. F. Redish 1 9/27/10 1 Physics 121 9/27/10 2 Physics 121 9/24/10 3 Physics 121 aFmnet=AB BAFF= “Net pForce “ = vector sum of all the pForces acting on the object.Physics 121 9/27/10 Prof. E. F. Redish 2 9/27/10 4 Physics 121 force) feeling(object force) causingobject ( F9/27/10 6 Physics 121 9/27/10 7 Physics 121Physics 121 9/27/10 Prof. E. F. Redish 3 9/27/10 8 Physics 121 mWa=9/27/10 11 Physics 121 gmWa==gmW=9/27/10 12 Physics 121Physics 121 9/27/10 Prof. E. F. Redish 4 9/27/10 13 Physics 121 WE m= mggg 9.8 N/kgWhat object causes W? Why N/kg instead of m/s2? 9/27/10 14 Physics 121 aFmnet=AB BAFF= A pForce is what two objects do to each other when they touch that can change each others’ velocities. Measured by the stretch of a spring. 9/27/10 15 Physics 121 a =Fnetm=WE mm=mgm=gPhysics 121 9/27/10 Prof. E. F. Redish 5 9/27/10 16 Physics 121 9/27/10 17 Physics 121 a =Fnetm=WE mm=mgm= ga= g =vtv =yty 9/27/10 18 Physics 121 g =vtv =ytvi= v0yi= 0 ti= 0vf= 0 yf= htf= Tg =vf vitf tiv =yf yitf tig =v0Tv =hTv =vi+ vf2=v02T =v0gv02=hTh =12v0T
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