Astronomy 1021 Lecture Notes - Lecture 6: Angular Momentum, Bohr Model, Thuban

• School: Western University
• Department: Astronomy
• Course: Astronomy 1021
• Professor: Robert Cockcroft

Document Summary

Speed of the planet depends on the distance from the sun, further from the sun means slower orbital speed. Velocity, v | x mass, m | momentum, p= mv. Acceleration, a | x mass, m | force, f= ma. The only way to change an objects momentum is to apply a force to it. The total momentum of interaction objects cannot change as long as there is no external force acting on them. Rotating object: no overall velocity, therefore no overall momentum. However, all pity are rotating, so these parts have angular momentum. Angular momentum is adding up the momentum of all the parts for a spinning or orbiting object- depends on velocity, mass and distribution of mass. Angular momentum- mass x (rotation) velocity x distance (l= mvr) Earth spins on its axis (every 24 hours), so earth has rotational angular momentum. Earth orbits around the sun ( every ~365 days) so earth also has orbital angular momentum.