AST101H5 Lecture 12: AST101 – Chapter Four.docx
Document Summary
How do we describe motions: speed change in position or location in some amount of time, = metres per second (m over s, examples: walking 1(m over s) running 10(m over s), driving 27. 8(m over s) = 100km/h, earth"s orbit speed = 30km/s = 108"000 lm/h, velocity change in (location + direction) in some amount (not the same as speed, units are m/s (same as speed, example: driving 100km"h west is not the same velocity as driving. Acceleration of gravity: dropping an object, v = 0 m/s @ 0s, v = 10m/s @ 1s, momentum = velocity times mass, note: momentum has direction because direction because velocity has direction, changing velocity changes the momentum, changing mass also changes momentum, momentum cannot change on its own, force is needed to change momentum, forces can cancel out, so only the sum of all forces = net forces change momentum.
