Honors Physics

# Memorization

## Equations

v = vo + at

v2 = vo2 + 2a(d-do)

d = do + vot + (1/2)at2

F = ma

Work = change in KE

Ft = mΔv

## Units

One meter/second is approximately two miles/hour.

force - Newton, pound

One Newton is approximately one-quarter pound.

work & energy - Joule, calorie, kilocalorie

calorie - energy needed to raise 1.0 g of water by 1.0 degree Celsius

power - Watt, horsepower

One horsepower equals 750 Watts (ten light bulbs).

One human being consumes an average of approximately 100 Watts.

## Basic Concepts & Definitions

Science is a way to answer measurable questions, a method of acquiring knowledge.

"Extraordinary claims require extraordinary evidence."

The Scientific Method: Make a prediction (hypothesis), then test your prediction (experiment).

velocity - speed and direction

acceleration - how quickly velocity changes

Three conclusions from Special Relativity: as an object approaches the speed of light, its length decreases, its mass increases, and its time slows down.

fact - a verified measurement

hypothesis - a testable guess

theory - a testable explanation. It is NOT an opinion, a guess, or "something that hasn't yet been proven." The word, used scientifically, is very similar to the way most people use the word "law."

Quantum Mechanics - the theory that describes behavior at the atomic level; locations of objects are described by probabilities

The four fundamental forces: gravity, electromagnetism, strong & weak (the nuclear forces)

fermions - fundamental particles of matter

bosons - particles that cause force; the exchange of bosons between fields causes force

inertial mass - a measure of how difficult it is to make something move; resistance to a CHANGE in motion.

Inertial mass is thought to be caused by two sources: energy (m=E/c2), and an interaction with the surrounding Higgs field. Check out this video: Your mass is NOT from the Higgs boson.

Newton's 1st Law of Motion: an object's motion cannot change without a force

Newton's 2nd Law of Motion: force = (mass)(acceleration)

Newton's 3rd law of Motion: Push something and it pushes back, with an equal force in the opposite direction. ALWAYS! (For every force, there is an equal and opposite force.)

General relativity - Einstein's theory of gravity. Mass bends the spacetime around it.

Big Bang theory in one sentence: The universe started very small, then expanded.

The 1st Law of Thermodynamics: Energy is ALWAYS conserved. It cannot be created or destroyed.

The 2nd Law of Thermodynamics: Entropy (disorder) always increases in an isolated system. In other words, whenever energy is used, some energy will be wasted (made useless).

energy - needed to do work

"Work transfers energy."

power - how quickly energy is used

impulse - causes a change in momentum

momentum - a measure of how difficult it is to make something stop; always conserved in the absence of external forces

rotational inertia (moment of inertia) - a measure of how difficult it is to make something spin; depends on mass and location of rotational axis

angular momentum - a measure of how difficult it is to make something stop spinning

torque - makes an object spin or stop spinning; rotational equivalent of force

Stress causes strain.

elastic - stretches but returns to original shape

plastic - stretches but remains deformed

resonance - an object being shaken at its natural frequency

Objective measures of sound: frequency, intensity and harmonics

Subjective perceptions of sound: pitch, loudness and timbre

electric field - surrounds electric charges; causes electric force

magnetic field - surrounds MOVING electric charges; causes magnetic force

current - moving charges; transfers energy in a circuit

resistance - resists current; wastes energy in a circuit

voltage - average electrical potential energy; supplies the energy to a circuit

Changing magnetic fields induce voltages.

The wave model of light - Changing electric field causes changing magnetic field; changing magnetic field causes changing electric field.

light waves - perpendicular sine waves, made of changing electric and magnetic fields

photon - a light particle; the boson that causes electromagnetic force