Physics 101 Introduction to Mechanics 

April 17 Angular Momentum  



Applications
of Conservation of Angular Momentum
If global warming proceeds during the this century as anticipated, it is possible that the polar ice caps will melt, substantially raising sea levels around the world (flooding coastal cities like New York, etc.). Would this shorten, lengthen or have strictly no effect on the duration of a day? (A "day "here means from one sunrise to the next one.) a. lengthen the say
Second law is simply conservation of angular momentum. That's it. This can be restated in terms of the area
swept out (dA) in some time interval (dt).
The area of the triangle can be found by taking 1/2 of the parallelogram's area dA= 1/2 R * v dt By using the definition of angular momentum (of a point particle) we can rewrite the triangle's area as dA= L/ 2m dt So, dA/ dt= L/ 2m= constant Angular momentum has to be conserved as
we only have a central force acting on the orbitting body (it cannot exert
a torque), so the body sweeps out equal areas in equal time intervals.
Kepler's second law implies that as a planet's distance from the sun increases in an elliptical orbit, its orbital speed a. increases


About the Course Syllabus Schedule Study Hints Problem Solving Contract BlackBoard Homework assignments & solutions Miscellaneous links About Dr. Jeff Feedback


