Physics Study Guide

Hey guys. I'm very excited that the science test has been moved to next week, however since I've been home sick all day I created a study guide. I don't know how to attach a word document, so sadly I will just have to to copy and paste. Also, Nick (not me! totally his idea!) wants me to say that he doesn't think we should have multiple study guides...so don't put yours up I guess. But, because I am not a blog control freak, if there is something that I didn't include on the study guide, I think it would be awesome if you just posted it yourself. PHYSICS STUDY GUIDE for 10/9

VOCABULARY
Acceleration = the rate at which velocity changes with time; the change in velocity may be in magnitude, or in direction, or in both. It is usually measured in m/s 2
Air resistance = the force of friction acting on an object due to its motion through air
Atoms = measurement of mass -- An atom consists of a dense nucleus of positively-charged protons and electrically-neutral neutrons, surrounded by a much larger electron cloud consisting of negatively-charged electrons. An atom is electrically neutral if it has the same number of protons as electrons. The number of protons in an atom defines the chemical element to which it belongs, while the number of neutrons determines the isotope of the element.
Average speed = TOTAL distance covered per amount of travel time
Constant velocity = (constant) speed and direction with no changes
Constant speed =
Density = a measure of mass per volume for a substance
Force = a push, or pull
Free fall = motion under the influence of only gravitational pull
Inertia = the property of things to resist changes in motion
Instantaneous speed = the speed at any given instant -- what a speedometer reads
Kilogram = one unit of mass.
Mass = The amount of matter in an object. It is the total weight of the atoms or molecules in the object. Mass is constant.
Speed = distance covered per amount of travel time
Velocity = speed AND the direction of motion -- a vector quantity
Weight = the force of gravity on an object -- measurement of force holding an object’s mass in place


SCIENTISTS & THEIR STUDIES
Aristotle on Motion
• Natural and Violent Motion
• Every object in the universe had a proper place and it was determined by its nature to get there – NATURAL
• However, all other unnatural motions were VIOLENT
• FOUR MAIN ELEMENTS: Earth, Water, Fire and Air
o Combinations of these elements would seek their natural place in the universe – depending on what percent of the element each object had within.
• ALL motions resulted from the nature of the moving object or from a sustained push or pull. If an object was in its “proper” place, it would not move unless subjected to force (except for celestial objects which moved in circular paths). The normal state was one of REST.
• His theories were beyond question for nearly 2000 years – until the 16th century because the earth must have been in its proper place, and a force capable of moving the earth was inconceivable, it seemed quite clear the earth did not move.
Copernicus
• Reasoned from astronomical observations that the earth traveled around the sun! Kept his thoughts from the public because he feared persecution and had doubts about himself. He could not reconcile the idea of the moving earth with the prevailing ideas of motion at that time.
Galileo
• Believes Copernicus – disproves Aristotle; finds that a stone twice as heavy as another did not fall twice as fast. Except for the small effect of air resistance, he found that objects of various weights would fall together and hit the ground at the same time.
• Galileo described motion in terms of time rates of change. Rates are speed, velocity and acceleration.
String Theory
• String theory is a model of fundamental physics, whose building blocks are one-dimensional extended objects called strings, rather than the zero-dimensional point particles that form the basis for the standard model of particle physics -- Exists on a quantum level rather than a universal


FORMULAS
Speed = distance / time
Average speed = total distance covered / time interval
Total distance covered = average speed X time
Acceleration = change of velocity / time interval