Physics Definitions

Vector

Vector

Measurement that includes magnitude and direction

Scalar

Measurement with only magnitude

Newton’s First Law

• The natural state of motion is constant velocity

• I the net force is zero, the velocity will be zeo as well (no acceleration)

Newton’s Second Law

• The harder you push, the more something will accelerate

• if it is massive, it will accelerate less well

• acceleration is directly proportional to net force

• acceleration is inversely proportional to mass

Newton’s Third Law

• one object exerts force on another object

• that object will exert an equally strong force back in the opposite direction

• ex) I punch you and break my finger on your face

Force of Gravity

Weight force associated with the gravitational field of an object

Normal Force

Force provided by a solid surface that is perpendicular/opposite to the force being exerted onto it

Friction Force

Force provided by a solid object that is perpendicular/opposite to the force being exerted onto ti

Tension Force

Pulling force from a string/rope/whatever

Gravitational Field

• every object has it

• gravitational fields pull towards themselves

• when something is put in a gravitational field, it is pulled towards the source

• the mass increases the strength of the field

• the distance decreases it

• g=Gmc/r^2

Electric Field

• field can pull towards or away depending on the charge of the field

• negative creates field towards

• positive creates field away

Mechanical Wave

A wave in which a physical medium is waving

Electromagnetic Wave

A non mechanical wave in which electric and magnetic fields are waving

Medium

The thing that is waving for a mechanical wave

Source

The thing that is disturbing the medium to create the wave

Pulse

One single disturbance of the medium

Transverse Wave

When the medium shakes perpendicular to the wave motion

Longitudinal Wave

When the wave shakes parallel to the wave motion

Crest

A “positive” pulse on a longitudinal wave

Trough

A “negative” pulse on a transverse wave

Compression

A “positive” pulse on a longitudinal wave

Rarefaction

A “negative ‘pulse on a longitudinal wave

Fixed End

When the end of the medium is held in place

Free End

When the end of a medium can move freely

Reflection

When a pulse encounters and end and bounces back

• it will invert if the end is fixed

• it will stay the same if it is free

Interference

When two pulses are in the same place or the same time

Constructive interference

Two of the same kinds of pulses crash and add together

Destructive Interference

Two opposite pulses crash and one subtracts from the other

Standing Wave

A special wave that is a result of the interference of two waves moving in the opposite direction

Node

A point on the standing wave that does not move

Antinode

A point on a standing wave that moves more than any other point

Fundamental Frequency

The lowest frequency that produces a standing wave

Overtone

Higher harmonics for standing waves

Period (T)

The time that it takes for one complete cycle of the disturbance

• one crest one trough

• one compression one rarefaction

Frequency (f)

The number of wave cycles that get completed per unit of time

• Inverse of Period

Wavelength (λ)

The distance moved by the wave is one full cycle

• often measured crest to crest/trough to trough

Amplitude (A)

This is the height of the crests/troughs

Light

• needs no medium to travel!

• electromagnetic fields are waving

• all moves at the same speed

Refraction

• the change in speed of a light wave as it passes through a medium

• n is the index of refraction

Reflection

• the medium has an index of refection or light has an angle that does not allow for the light to pass through a substance

• the medium doesn’t absorb any light or allow any through, so it bounces off

What is the order of electromagnetic waves

radio, mico, infrared, visible light, ultraviolet, x ray, gamma ray

Position/Time Graph

• rise = displacement

• run = time

• slope = velocity

Velocity/Time Graph

• rise = velocity

• run = change in time

• slope = acceleration

• area = displacement