ASTRO-110 Lecture Notes - Lecture 6: Momentum, Kinetic Energy, Potential Energy
Document Summary
Weighing the earth finding the mass if we are standing still on the earth, the force of gravity between the earth and ourselves is our weight. With any sphere, the gravitational force on the surface is the same as it at any one point on the sphere and use the radius (need the radius to tell weight) Newton never knew the value of his constant but he was able to use his laws of motion and law of gravity to explain why kepler"s laws are true. For any force, there always is an equal and opposite reaction force. Energy is conserved in systems because of the 3rd law. Momentum is another quantity conserved in systems because of the 3rd law linear momentum: p=mv: angular momentum: l=mvr. Momentum: linear momentum: if there are no forces acting on an object, it doesn"t change its velocity its momentum is conserved.
