1 Physics 101Thursday 9/15/11Class 7Chapter 5.3 – 5.5Newtonʼs Second law of motionNewtonʼs Third law of motionForces in 2 dimensionsIn the SI (metric) system, the unit of force is the .. A) Galileo Reading Quiz Newton's 1st LawYou kick a smooth flat stone out on a frozen pond. The stone slides, slows down, and eventually stops. You conclude that: A) the force pushing the stone forward finally stopped pushing it B) no net force acted on the stone C) a net force acted on it all along D) the stone simply “ran out of steam” E) The stone has a natural tendency to be at rest Newton's 2ndLawNewton's 2ndLaw: Solving problems with this: 1) Sketch the Forces 2) Isolate the particle of interest 3) Choose a convenient coordinate system 4) Resolve Forces into components with this coordinate system 5) Apply the 2ndlaw to each component !F=m!a
9/15/11 2 Newton's 2ndLaw 1-DSituation I: A constant force is exerted for a short time interval on a frictionless cart that is initially at rest. The cart acquires a final velocity vf. (1D Motion) v .. .