Show pageOld revisionsBacklinksBack to top This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong. ===== Pre-lecture: Momentum and Momentum Principle ===== * Changes in motion; you pay attention to how an object changes it position * Define momentum - some objects are easier to change their motion than others * $\vec{p} = \gamma m \vec{v}$ is a vector concept; points in direction of velocity vector for a system; complete and alway applies * Define $\gamma$ * $\gamma$ starts to matter at high speeds; less than about 300 km/s $\gamma \approx 1$ * $\vec{p}=m\vec{v}$ * The motion of a system is governed by the momentum prinicple * Big idea: Forces cause changes in a system's momentum; specifically the net force (define momentarily) * N1: An object that experiences no net force moves with constant velocity and vice-versa * N2 (MP): The quantitative description is $\Delta \vec{p} = \vec{F}_{net}\Delta t$. * What is a force...and...the net force? * Where the's calculus? * This description is an average force over a time interval; if the time interval shrinks, we get that the net force is the derivative of the momentum. * Another way to represent: force vs time graphs * More calculus area under the curve gives change in momentum temp/prelec/momentum.txt Last modified: 2014/07/17 12:59by caballero