Physics nat 5 every topic

two types of waves

longitudinal and transverse

longitudinal waves (diagram)

transverse waves (diagram)

example of longitudinal wave

sound is the ONLY longitudinal wave

examples of transverse waves

water, light, x-rays and radio waves

what is a longitudinal waves?

a wave in which the particles vibrate in the same direction as the wave travels

what is a transverse wave?

a waves in which the particles vibrate at 90 degrees to the direction the wave travels

frequency

the number of waves per second

speed of wave formula:

frequency is measured in (units) ?

Hertz (Hz)

period

time for one wave

diffraction

is the bending of waves around obstacles

__________ ______ diffract more

longer waves

why is reception better in hilly areas? (diffraction)

radio waves have a longer wavelength, they can therefore diffract more around hills and so can be picked up more easily.

diffraction (diagram)

pitches (frequency of waves)

loudness (frequency of waves)

high frequency=

higher pitch

low frequency=

low pitch

small amplitude=

quiet

large amplitude=

loud

speed of sound in air

340 m/s

speed of light in air

3x10^8 m/s

m/s =

ms-1

sound levels are measured in?

decibels (dB)

what can sound be measured by?

a sound level meter

examples of unwanted noise:

construction work, airplanes, motorway noise

sounds which continue for a long period of time over ____dB can damage hearing

85

workers who work in nosy environments must wear ____ _____________ to prevent permanent hearing damage

ear protectors

refraction

the change in the velocity of light when changing medium

the light will only bend if it strikes the surface at an _________

angle

refraction in glass

less dense to more dense material

lights refracts towards the normal

more dense to less dense

light refracts away from the normal

i is the angle of ___________

incidence

r is the angle of ____________

refraction

two types of lenses

concave and convex

concave lense

convex lens

kilo (K)

x1000

mega (M)

x1000000

milli (m)

÷ 1000

micro (μ)

÷ 1000000

speed formula

instantaneous speed formula

acceleration

the change in velocity in 1 second

symbol for acceleration

A

unit for acceleration

ms-2

an acceleration of 2ms-2 means a ____________ _________ of 2ms-2 every second

velocity increase

acceleration formula

speed time graph

speed time graphs show the ______ of a vehicle over a period of time

motion

the gradient of the speed time graphs gives you the ___________

acceleration

the area under the speed time graphs gives you the ___________ ____________

distance travelled

friction can be reduced by:

streaming lining, reducing area of contact, lubrication, ball bearings

friction can be increased by:

aerofoils, large surface area, type of material used

friction

a FORCE which opposes the motion of an object

friction when moving through is called?

air resistance

friction when moving through water is called?

drag

forces are a ______ or a _____

push, pull

forces can cause a change in:

shape, speed or direction

until for forces

newtons (N)

force can be messed using a __________ _________

newton balance

the mass of an object is the ________ everywhere

same

weight formula

newtons 1st law:

if forces are balanced an object will remain at rest or remain moving at a constant speed

newtons 2nd law:

if forces are unbalanced an object will accelerate in the direction of the unbalanced force

force formula

work done formula

energy work done

work is done when 'energy has been transferred'. to do this a force must be applied over a distance

gravitation potential energy formula

gravitation potential energy

when work is done to raise an object up against gravity, the energy is store as 'gravitational potential energy.

kinetic energy formula

kinetic energy

the energy associated with an object when it is moving, energy has to be proportional to its mass and speed squared

a ball being dropped: the energy change involved

Ep (top)= Ek(bottom)

an object sliding down a slope: the energy change involved

no friction: Ep (top)= Ek(bottom)

with friction: Ep (top)= Ek(bottom) + Ew

a pendulum swinging: the energy change involved

Ep (top)= Ek(bottom) = Ep(top)

two types of electrical charge

postive (+) and negative (-)

static electricity

if the charges build up on an object and stay still

lamp symbol

battery symbol

switch symbol

resistor symbol

variable resistor symbol

motor symbol

voltmeter symbol

ammeter symbol

fuse symbol

conductor

the electrons are free to move, when connected to a battery all electrons flow in same direction which is called an electric current

insulator

the electrons are not free to move and no current flows

electric current

the charge passing a point in 1 second

units for electric current

amperes (A)

electric current measured by _________

ammeter

electric current formula

Q= I x t

two types of electric current

AC (alternating current) and DC (direct current)

current diagrams

capacitor symbol

only allows AC to flow

diode symbol

only allows DC to flow

potential difference (voltage)

the energy transferred to each column of charge