All Combined Science Physics

force, mass, acceleration

force = mass x acceleration

acceleration, start and end velocity

acceleration = change in velocity / time

weight, mass, gravitational field strength

weight = mass x gravitational field strength

force, spring constant, acceleration

force = spring constant x extension

work done, force, distance

work done = force x distance

power, energy transferred, time

power = energy transferred / time

gravitational potential energy, mass, gravitational field strength, change in height

gravitational potential energy = mass x gravitational field strength x change in height

kinetic energy, mass, speed

kinetic energy = 1/2 x mass x speed^2

momentum, mass, velocity

momentum = mass x velocity

current, charge, time

current = charge / time

potential difference, work done, charge

potential difference = work done / charge

potential difference, current, resistance

potential difference = current x resistance

power, current, potential difference

power = current x potential difference

energy, potential difference, charge

energy = potential difference x charge

efficiency, various energy values

efficiency = useful energy output / total energy input

efficiency, various power values

efficiency = useful power output / total power input

moment, force, distance

moment = force x perpendicular distance from pivot

pressure, force, area

pressure = force / area

wave speed, frequency, wavelength

wave speed = frequency x wavelength

density, mass, volume

density = mass / volume

accurate

a measurement is considered accurate if it is judged to be close to the true value

anomalies

results that do not match the pattern seen in the other data collected or are well outside the range of other repeat readings (outliers)

bar chart

used when you have a categoric independent variable and a continuous dependent variable

categoric variable

categoric variables have values that are labels. For example, types of material

continuous variable

can have values (called a quantity) that can be given by measurement (for example, mass, volume, temperature, etc.)

dependent variable

the variable for which the value is measured for each and every change in the independent variable

directly proportional

a relationship that, when drawn on a line graph, shows a positive linear relationship that crosses through the origin

errors

sometimes called uncertainties

fair test

a fair test is one in which only the independent variable has been allowed to affect the dependent variable

hazard

a hazard is something (e.g., an object, a property of a substance or an activity) that can cause harm

hypothesis

a proposal intended to explain certain facts or observations

independent variable

the variable for which values are changed or selected by the investigator

line graph

used when both variables are continuous. The line should normally be a line of best fit, and may be straight or a smooth curve

precise/precision

a precise measurement is one in which there is very little spread about the mean value. Precision depends only on the extent of random errors - it gives no indication of how close results are to the true (accurate) value

prediction

a forecast or statement about the way something will happen in the future

random error

differences in results due to poor measurements being made. Usually this is because the experimenter does not carry out exactly the same method each time, or because of limitations of the measurement device

range

the maximum and minimum values of the independent or dependent variables

relationship

the link between the variables that were investigated

repeatable

a measurement is repeatable if the original experimenter repeats the investigation using the same method and equipment and obtains the same or precise results

reproducible

a measurement is reproducible if the investigation is repeated by another person, using different equipment and the same results are obtained

risk

the likelihood that a hazard will actually cause harm

systematic error

cause readings to be a value other than the true value, due to results differing from the true value by a consistent amount each time a measurement is made

valid

suitability of the investigative procedure to answer the question being asked

variable

physical, chemical or biological quantity or characteristic

alternator

an alternating current generator

dynamo

a direct-current generator

electromagnet

an insulated wire wrapped round an iron bar that becomes magnetic when there is a current in the wire

electromagnetic induction

the process of inducing a potential difference in a wire by moving the wire so it cuts across the lines of force of a magnetic field

Fleming's left-hand rule

a rule that gives the direction of the force on a current-carrying wire in a magnetic field according to the directions of the current and the field

generator effect

the production of a potential difference using a magnetic field

induced magnetism

magnetism of an unmagnetised magnetic material by placing it in a magnetic field

magnetic field

the space around a magnet or a current-carrying wire

magnetic field line

line in a magnetic field along which a magnetic compass points - also called a line of force

magnetic flux density

a measure of the strength of the magnetic field defined in terms of the force on a current-carrying conductor at right angles to the field lines

motor effect

when a current is passed along a wire in a magnetic field, and the wire is not parallel to the lines of the magnetic field, a force is exerted on the wire by the magnetic field

solenoid

a long coil of wire that produces a magnetic field in and around the coil when there is a current in the coil

split-ring commutator

metal contacts on the coil of a direct current motor that connects the rotating coil continuously to its electric power supply

step-down transformer

electrical device that is used to step-down the size of an alternating potential difference

step-up transformer

electrical device that is used to step-up the size of an alternating potential difference

transformer

electrical device used to change an (alternating) voltage. See also step-up transformer and step-down transformer

carrier waves

waves used to carry any type of signal

charge-coupled device (CCD)

an electronic device that creates an electronic signal from an optical image formed on the CCD's array of pixels

contrast medium

an X-ray absorbing substance used to fill a body organ so the organ can be seen on a radiograph

electromagnetic spectrum

the continuous spectrum of electromagnetic waves

ionisation

any process in which atoms become charged

microwaves

electromagnetic waves between infrared radiation and radio waves in the electromagnetic spectrum

optical fibre

thin glass fibre used to transmit light signals

radiation dose

amount of ionising radiation a person receives

radio waves

electromagnetic waves of wavelengths greater than 0.10m

ultraviolet radiation (UV)

electromagnetic waves between visible light and X-rays in the electromagnetic spectrum

wave speed

the distance travelled per second by a wave crest or trough

white light

light that includes all the colours of the spectrum

amplitude

the height of a wave crest or trough of a transverse wave from the rest position. For oscillating motion, the amplitude is the maximum distance moved by an oscillating object from its equilibrium position

compression

squeezing together

echo

reflection of sound that can be heard

electromagnetic waves

electric and magnetic disturbances that transfer energy from one place to another

frequency

the number of wave crests passing a fixed point every second

longitudinal waves

waves in which the vibrations are parallel to the direction of energy transfer

mechanical wave

vibration that travels through a substance

oscillate

move to and fro about a certain position along a line

primary seismic wave (P-wave)

longitudinal waves that push or pull on the material that they move through as they travel through the Earth

rarefaction

stretched apart

reflection

the change of direction of a light ray or wave at a boundary when the ray or wave stays in the incident medium

refraction

the change of direction of a light ray when it passes across a boundary between two transparent substances (including air)

secondary seismic wave (S-wave)

transverse waves that shake the Earth side to side as they pass through

seismic waves

sound wave at frequency greater than 20 000 Hz (the upper frequency limit of the human ear)

speed

the speed of an object (metres per second) = distance moved by the object (metres) ÷ time taken to move the distance travelled (seconds)

transmission/transmitted

a wave passing through a substance

transverse wave

a wave where the vibration is perpendicular to the direction of energy transfer

ultrasound wave

sound wave at frequency greater than 20 000 Hz (the upper frequency limit of the human ear)

vibrate

oscillate (move to and fro) rapidly about a certain position

wavelength

the distance from one wave crest to the next

upthrust

upthrust the upward force that acts on a body partly or completely submerged in a fluid

pressure

the force applied divided by the area it is applied to

braking distance

the distance travelled by a vehicle during the time it takes for its brakes to act

conservation of momentum

in a closed system, the total momentum before an event is equal to the total momentum after the event. Momentum is conserved in any collision or explosion, provided no external forces act on the objects that collide or explode

directly proportional

a graph will show this if the line of best fit is a straight line through the origin

elastic

a material is elastic if it is able to regain its shape after it has been squashed or stretched

extension

the increase in length of a spring (or a strip of material) from its original length

gravitational field strength, g

the force of gravity on an object of mass 1 kg (in newtons per kilogram, N/kg). It is also the acceleration of free fall