Physics grade 10 - EOYT

what is an oscillator?

system of repeated motion around an equilibrium position

what is the equilibrium?

position where forces are balanced and a system is stable. (wants to return to this position)

what is the time period

the time it takes to complete one cycle

what is the amplitude

the furthest point from the equilibrium

what is the frequency (formula?)

number of cycles per second. Slows down = increase in frequency.

f=1/T

where f is frequency and T is time period.

precision

reliability of result

accuracy

closeness of a measurement to the true value

what is the epicenter

The point on the Earth's surface directly above where an earthquake originates, indicating the location of the seismic event.

2 types of waves

longitudinal and transverse waves.

P waves =

primary waves (longitudinal) that are compressional and travel through solids and liquids.

(like sound waves)

S waves =

secondary waves (transverse) that are shear and only travel through solids.

(like waves of the sea)

S vs P waves

S waves = slower, move up down, displacement of the medium is perpendiclar to the propagation of the wave

P waves = faster, move back and forth, displacement of the medium parallel to the propagation of the wave.

displacement time graphs show

one molecule in the wave as time progresses. It illustrates how the position of a particle changes over time as the wave propagates. - use time period for 1 cycle

displacemnt distance graphs show

the instant shape of the wave (like a picture) – use wave length – lagdma for a cycle

(of waves) A =

amplitude

(of waves) F =

frequency (f=1/t)

(of waves) C =

crest

(of waves) T =

trough or time period

(of waves) lagdma =

wave length

(of waves) V =

speed of wave

wave front model

shows the crests of a wave (usually) can show the frequency and the shape but not the direction.

High frequency causes wavelength to

decrese

Low frequency causes wavelength to

increase

(of waves) if there is a change in medium

f = stays constant

v = changes (speeds up or slows down)

lagdma has to change accordingly

echolocation

makes use of refracted sound waves to find objects (whales, dolphins, bats)

calculations, echolocation

s=vt

where s = 2 ties the distance because it has to go and come back. can be replaced by 2d for simplicity

where v = speed

where t = time taken.

what does light need?

a source (blub) a medium (air) and an observer (person)

examples point source (luminous)

eg. laser, lamp, sun

examples extended source (luminous)

LED screen, LED’s, smartboard

examples extended source (non-luminous)

wall, cloud, rainbow

examples point source (non-luminous)

moon, (e.g., because the sun reflects its light off the moon), planets

Ray model

is used to represent light, shows direction no wavelength.

a collection of parallel rays is a _____

beam

penumbra

is a half shade (half umbra) that forms when an extended source is casting a shadow.

If the extended source moves closer to the object, the penumbra increases – the umbra stays the same. if it moves further, the penumbra decreases.

If the object blocking the light moves closer (to the light), penumbra increases. if it moves further from the light, it decreases.

umbra

A different word for shade, in this case ‘full shade’ or ‘full umbra', can be formed with an extended or point source. But in an extended source, penumbra is also formed.

law of reflection

i = r

i = the angle of incidence

r = angle of reflection

specular reflection

a surface in which you can see yourself, pan, glass, metal, shiny plastic… (you are mirrored due to rays crossing)

diffuse reflection

When the surface is rough so the light scatters, you are unable to see your reflection.

2 types of curved mirrors

concave - converging

convex - diverging

(in mirrors) P =

pole of mirror,

(in mirrors) Principle axis =

line thorugh the center (like the equator of the earth)

(in mirrors) F =

focus (or focal length)

(in mirrors) C =

center of curvature (the center if the circle were to be compleated)

(in mirrors) the normal has to be drawn through the _____

center of curvature

in concave mirrors, the image is where the ________

Reflected rays cross. (draw 3 rays – one parallel to the principal axis, then reflected through F, and another through F and then parallel to the principal axis, then one that goes through the center and gets refected back on the same path)

speed of light

represented by C = 3×10⁸ ms^-1

refracted index formula

n=C/Cm

c = speed of light

cm = speed of light in the medium

n = refracted index

refractive index AIR

= 1

refractive index WATER

= 1.33

refractive index GLASS

1.48-1.56 - depends on type

if it moves from a lower refractive index to a higher one it ________

slows down (towards the normal)

if it moves from a higher refractive index to a lower one it ________

speeds up (away from the normal)

snells law

n₁sin()₁=n₂sin()₂

where () = theta

critical angle causes

TIR (total internal reflection)

criticaol angle formula

()_c=sin^-1(n₂/n₁)

where () = theta

Mirage occurs when….

air is cold, ground is hot

a mirage is ……

when layers of cold to hot air form, causing the light from an object to be refracted at a larger angle each time until the critical angle is hit. Then it reflects back up.

fiber optic cable

The skinnier it is, the closer it is to the critical angle.

2 types of lenses

convex converging, concave diverging

convex lenses cause light to …

converge into a single point (thinner = less difference in angle of the ray)

concave lenses cause light to…

diverge (spead out)

convex lens diagram

• uses arows on the y axis (to show its shape)

• F₂ is on the left, F₁ is on the right

• shorter F = stronger lense = more change in angle

concave lens diagram

• uses inverted arrows on the y axis (to show it goes inwards)

• F₁ is on the left, F₂ is on the right.

where do you find convex lenses

• telescope (needs to show a large picture in small)

• magnifying glass (needs to show a small object in big)

• webcams (laptop) (needs to show a large picture in small)

where do you find concave lenses

• light house (diverges light)

(in lenses) Mg =

magnification = h2/h1or v/u

(in lenses) H1 =

object height

(in lenses) H2 =

image height

(in lenses) U =

object distance

(in lenses) V =

image distance

(in lenses) F =

focal length

lens formulas

1/f=1/u+1/v - It is used to determine the lens properties or to find where an image will be formed given the object's position and the lens's focal length.

h₁/f=(h₁+h₂)/v - It can be used to find the image height or image distance given other parameters.

h₁/u=h₂/v - It is often used to calculate magnification and to find unknown heights or distances in lens systems.

Vector is a

quantity with magnitude and direction

Scalar is a

quantity with magnitude but no direction

examples of scalars

distance, speed

examples of vectors

displacement, velocity, aceleration

suvat equations

v=u+at

s=vt-(1/2)at²

s=ut+(1/2)at²

s=(​(u+v)/2)t

v²=u²+2as

freefall

falling when gravitational force is the only force acting on you (no air resistance)

terminal velocity

what the gravitational force is equal to the air resistance (when falling)

a or g= ____ on earth

9.81 ms⁻²

distance-time graphs slope =

speed

displacement-time graphs slope =

velocity

speed-time graph slope =

acceleration (without direction indicated)

Velocity-time graph slope =

acceleration (with direction)

area under a velocity-time graph shows

displacement

area under speed-time graph shows

total distance travled

kinematics

motion under constant acceleration (assume a=9.81)

dynamics

forces and acceleration – you cant see the force, only the effect of the force.

work

energy transformation from one form into another.

contact force =

tempoary deformation (eg. stub toe)

non contact force =

no contact involved (e.g., gravity)

list contact forces

• elastic

• normal (reaction)

• tension

• friction

• air resistance

• applied

• bouyancy

all forces (exept normal) are drawn from the area they are acted upon (eg. side top bottom)

list non contact forces

• magnetic

• gravitational

• nuclear

• electrostatic

all forces are drawn from the center of the object

what types of changes do we see from forces

• change in acceleration

• change in the shape – elastic or (bounces back to initial shape) or plastic (stays deformed)

• change in direction

doppler shift

the change in sound frequency due to movement

without interaction there is no _____

force

newtons first law

An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force. (aka inertia)

W=mg

g = 9.81

m = mass

w = wieght

newton’s second law

F=ma

where F is force, m is mass, and a is acceleration.

where a is proportional to F