physics theory

scalar

values with only magnitude and no direction

vector

values with magnitude and a direction

what graph is this? whats the equation and proportion of it?

linear! y=mx and y ∝ x

what graph is this? whats the equation and proportion of it?

power! y=kx² and y ∝ x²

what graph is this? whats the equation and proportion of it?

inverse! y/x and y ∝ 1/x

what graph is this? whats the equation and proportion of it?

inverse square! y=k/x² and y ∝ 1/x²

**HINT! it drops faster than inverse

what graph is this? whats the equation and proportion of it?

square root! y=√x and y ∝ √x

position

the location of an object relative to a reference point

displacement

the change of position

velocity

the rate of change of position

acceleration

the rate of change of velocity

direction of acceleration

the direction of displacement and velocity is always the same, but acceleration depends. if speeding up, acceleration is the same as displacement and velocity, if slowing down acceleration is the other way.

free fall rules

1. if an object is thrown upwards into the air, to find the highest high of the object use: v2= 0m/s

2. if an object is thrown up into the air and eventually returns to the same position, its initial and final velocity are related: v1=v2

3. if an object travels upward and changes direction, the overall displacement and distance are different! the equation only requires displacement

what does the slope of a position vs time graph represent?

velocity, specifically constant velocity! NOTE: IF THE SLOPE IS CURVING UPWARDS IT REPRESENTS SPEEDING UP, IF THE SLOPE IS CURVING DOWNWARDS IT REPRESENTS SLOWING DOWN

gravitational force

the gravitational force is an attractive force that all objects exert on each other and is dependent on the object’s masses.

weak nuclear force

the weak nuclear force between subatomic particles

electromagnetic force

the force that charged particles exert on each other it is responsible for most forces

strong nuclear force

an attractive force that holds protons and neutrons in the nucleus of the atom

forces from strongest to weakest

strong, electromagnetic, weak, gravity

newtons first law

an object at rest will remain at rest, an object in motion will remain in motion unless acted on by the unbalanced force. this law is also know as the law of inertia.

inertia

an objects ability to resist change in motion, related to its object’s mass

newtons second law

an object’s acceleration is determined by the net force exerted on it by its environment and by the object’s mass.

direct proportion F ∝ a

if one increases/decreases, the other does the same. if force increases, acceleration increase. if force decreases, acceleration decreases.

inverse proportion m ∝ 1/a

if one increases or decreases, the other does the opposite. if mass increases, acceleration decreases. if mass decreases, acceleration increases.

applied force

push or pull, by hand, foot, etc

tension force

force due to rope and string

friction force

force between two surfaces that are moving or try to move relative to each other

normal force

force due to a surface acting on an object

force of gravity

force of the earth (or planet) pulling an object down towards its centre

newtons third law

force always comes in pairs. every force is an interaction between two objects. ex) when u slap the table the table slaps u

galileo’s law of falling

two objects that r dropped together will fall together regardless of their shapes and amsses

difference between mass and weight

mass is the amount of MATTER an object has

weight is a force measured in N

what does it mean to be an “at a distance” force?

this means that a force exists between two objects even when they are not touching!

what is the difference between “force of gravity” and “acceleration due to gravity”?

acceleration due to gravity is the acceleration all objects experience when falling (-9.8)m/s²

force of gravity is the force that is put upon the object to make it fall at a rate of (-9.8)m/s²

terminal velocity

when an object or person is falling from a great height, the air resistance becomes greater thus making acceleration due to gravity and air resistance equal and balance each other out. Eventually it makes acceleration stop and creates terminal velocity.

static friction

friction that occurs when an object IS NOT moving ex. car parked on a hill, box on a ramp and is not sliding

static friction is stronger than kinetic friction

kinetic friction

frictions that occurs when an object IS moving (sliding), ex. a box sliding across the floor, rubbing ur hands together

kinetic friction is weaker than static friction

coefficient of friction

represents the frictional force resisting the motion of two surfaces

μ = Ff/FN || 0 < μ < 1

gravitational field strength

a space around a mass where a test mass experiences a force

describe when mass appears heavier than normal

1. moving up fast

2. moving down, slowing down

   a > 0 (acceleration is positive)

describe when mass appears lighter than normal

1. moving up, slowing down

2. moving down, speeding up downwards

   a < 0 (acceleration is negative)

describe when mass’s actual and apparent weight are equal

1. not moving

2. moving up or down WITH constant velocity

   a = 0

electric charge

describes whether an object has an excess or deficit of electrons relative to protons

induced charge seperation

the shift in electrons

magnetic dipole

a north/south pair

temporary magnets

a magnet that lose their magnetism over time, especially when dropped, heated or hammered

what r magnets made out of?

IRON, NICKEL, COBALT! materials like this are called ferromagnetic!

magnetic field lines

run from north pole to south pole outside of the magnetic, run from south pole to north

domain theory

ferromagnetic materials consists of dipoles, each dipole is like a little magnet with north and south heh! areas called DOMAINS have dipoles that all point in the same direction, the more aligned the domains are the more magnetized it is.

magnetic declination

the angle between true north and magnetic north

magnetic inclination

aka the magnetic dip, the angle that the magnetic field makes with the surface of the earth

auroras

caused by high-energy particles from the solar wind trapped in the earth’s magnetic fields. when electrons collide with oxygen and nitrogen particles, omitting a light that we see as auroras!!

what is a wave?

a wave is a rhythmic disturbance that carries ENERGY through matter or space.

longitudinal waves

the particles in the medium move PARALLEL to the motion of the wave.

transverse waves

the particles in the medium move PERPENDICULAR to the direction of the wave.

mechanical wave

a transfer of energy where A MEDIUM IS REQUIRED! ex. water waves, sound waves

electromagnetic wave

a wave that can transfer energy WITHOUT A MEDIUM! ex. visible light, gamma rays

amplitude

how big the wave is, the maximum displacement. it represents how much energy the wave has.

wavelength

the horizontal distance between corresponding points on the consecutive wave crests.

crest

the highest point of a wave.

trough

the lowest point of a wave.

period

the time it take for ONE WAVELENGTH to pass a given point. hint: TU VELO IS ONE PERSON!! PERIOD!

frequency

the NUMBER OF WAVELENGTHS that pass a given point per second. 1 hertz is 1 wave per second!

the speed of wave is constant if?..

…if the medium it travels through stays constant!

reflection

when waves bounce off of an obstacle

a pulse that reflects from a fixed-end is…

..horizontally and vertically inverted. a CREST becomes a TROUGH and a TROUGH becomes a CREST.

a pulse that reflects from a free end is…

…ONLY horizontally inverted. the crests and troughs remain the SAME.

transmission

when waves move from one medium to another medium.

less dense to a more dense

for the transmitted pulse the orientation stays the same, the amplitude gets smaller, the wavelength gets smaller and it travels slower.

for the reflected pulse the orientation inverts, the amplitude gets smaller, the wavelength remains the same.

more dense to a less dense

for a transmitted pulse the orientation stays the same, the amplitude gets longer, the wavelength gets longer and it travels faster.

for the reflected pulse the orientation stays the same, the aplituder gets smaller, the wavelength stays the same, and its the same speed of the original pulse.

mr wegley attaches a slinky to the wall and begins introducing pulses with different amplitudes and then different wavelengths, why would all the pulses reach the wall at the same time?

regardless of the amplitude, the speed of the pulse is maintained by the properties of the medium.

the wavelengths of a wave doesn’t have any affect on the time.

interference

when two or more waves meet

constructive interference

two waves with the same frequency and phase will merge together and get bigger! (crest + crest ; trough + trough)

destructive interference

two waves with the same frequency and OPPOSITE phase will cancel eachother out. (crest + trough)

standing wave

caused by constructive and destructive interference

nodes

caused by complete destructive interference, they have NO amplitude.

anti-nodes

caused by complete constructive interference, they have MAXIMUM amplitude

wave front

the whole width of the wave crest

wave ray

an arrow drawn perpendicular to the wave front

refraction

when waves bend when they move from one medium to another due to a change in speed

resonance

when a medium vibrates at its natural frequency in response to an external sound wave. ex) singing and breaking a glass.

how does a sound wave move?

its moves by molecules bumping into each other

diffraction

when waves bend around an obstacle

what is the doppler effect?

the apparent change in frequency an observer hears based on the relative motion of the source.

the visible spectrum ranges around?

-400 (violet) to 700 (red) nanometres

what are the two laws of reflection of light

1. the incident angle is equal to the angle of reflection.

2. the incident ray, the normal and the reflected ray all lie in the same plane. (they all lie on the same surface)

specular reflection

light that reflects off of a smooth surface

diffuse reflection

light that reflects off of a microscopically rough surface

which way would light bend from a more dense to less medium?

light will move AWAY from the normal.

which way would light bend from a less dense to more dense medium?

light will bend TOWARDS the normal

index of refraction

the property of a material indicating how much speed of light is reduced, it CANNOT be smaller than one. ex) n1 = 1 (air)

dispersion

when white light separates into colours and create a random effect.

stationary sound source

when a person hears the same pitch regardless of the location

what did newton contribute

1. the laws of newton, object @ rest remain @ rest, EF=ma, action reaction

2. law of gravity, every particle attracts every other particle in the universe

3. light dispersion, white light can be separated into different colors

4. particle theory for light bc light move fast

what did milikan contribute

1. oil drop experiment to find voltage and size of a singular charge || q=mg/E

what did huygens contribute

1. wave theory of light bc it can diffract

what did young’s contribute

1. discovered the interference created during double slit experience