ASTR 20 Lecture Notes - Lecture 19: Net Force
Document Summary
Speed: rate at which object moves; speed=distance/time. Velocity: speed and direction; example: 10 m/s, due east. Acceleration: any change in velocity; units of speed/time (m/s^2) You can have acceleration not equal to zero, but velocity equal to zero. True: if you start with a constant velocity, then accelerate in the opposite direction, your velocity will reduce to zero and then increase. You can have acceleration equal to zero, but velocity not equal to zero. You can accelerate without changing your speed. True: a change in direction is a form of acceleration, and it is possible to change direction (and velocity) while keeping the speed constant. Speed increases by 10 m/s with each second of falling. Galileo showed that g is the same for all falling objects, regardless. A net force changes momentum, and produces an acceleration (change in velocity) The rotational momentum of a spinning or orbiting object is known as angular momentum.
