IGCSE physics

What is the difference between speed and velocity

velocity has direction

what is the equation relating average speed, time taken and distance moved?

average speed=distance moved/time taken

what is acceleration?

how quick velocity is changing

what is the equation relating acceleration, change in velocity and time taken?

acceleration=change in velocity/time taken

on a distance-time graph what does the gradient symbolise?

speed

on a distance-time graph what does it mean when there's a flat section?

it's stopped

on a distance-time graph what does it mean when there are curves?

there's acceleration or deceleration

on a velocity-time graph what does the gradient symbolise?

acceleration

on a velocity-time graph what does it mean when there is a flat section?

steady speed

on a velocity-time graph how can you find distance travelled in a certain time?

by working out the area under the line (with limits if trying to find the distance travelled between certain time)

what is weight caused by?

gravity

what is gravity?

the force of attraction between all masses

mass includes the force of gravity. true or false?

false

give the equation relating weight, gravitational field strength and mass

weight=mass x gravitational field strength

what does friction do?

slows things down

what is the accelerating force that acts on all falling objects?

gravity

what is terminal velocity?

resistance force=accelerating force

what is newton's first law?

balanced forces means no change in velocity

what is newton's second law?

an unbalanced force means there will be acceleration

give the equation relating force, acceleration and mass

force=mass x acceleration

what is newton's third law? (use object A and object B)

that if object A exerts a force on object B, object B with exert the same but opposite force on object A

what is a scalar quantity?

a quantity which has size

what is a vector quantity?

a quantity which has size and direction

which ones of these are vector quantities?

- mass

-force

-velocity

-temperature

-time

-distance

-displacement

-acceleration

-momentum

force, velocity, displacement, acceleration, momentum

which ones of these are scalar quantities

- mass

-force

-velocity

-temperature

-time

-distance

-displacement

-acceleration

-momentum

mass, temperature, time, distance

what factors affect thinking distance?

speed, how dopey you are

what factors affect braking distance?

-speed

-mass of the vehicle

-quality of the breaks

-road surface

give the equation relating momentum, velocity and mass

momentum=mass x velocity

when is momentum conserved?

when no external forces act

what causes changes in momentum?

force

give the equation relating force acting, change in momentum and time taken for change to happen

force acting=change in momentum/time taken for change to happen

how do crumple zones help decrease the impact of a crash on a passenger?

they increase the time for the car to stop

how to seat belts help decrease the impact of a crash on a passenger?

they increase the time for the passenger to stop

how to air bags help decrease the impact of a crash on a passenger?

they slow the passenger down

what is moment?

the turning effect of a force

give the equation relating moment, force and distance

moment=force x distance

what is the centre of gravity of an object?

where the weight of the body acts

how can you find the centre of gravity in simple shapes? eg. a square

by looking at the point where lines of symmetry join

what does hooke's law say?

that extension is proportional to force

when does hooke's law stop?

when the force is great enough

what happens when you increase a force past the elastic limit?

the material will be elastically deformed

what galaxy is our solar system in?

milky way galaxy

what is a galaxy?

a large collection of stars

how many stars are there in our galaxy?

billions

what is the force that keeps the stars together in the galaxy?

gravity

what is the force that causes orbits?

gravity

what is an orbit?

a balance between the forward motion of the object and a force pulling it inwards

give an example of an artificial satellite

the moon

what are comets?

small lumps of icy rock which orbit the sun

what type of orbit does a comet have?

elliptical (where the sun is near one side of the orbit)

how many days does it take for the earth to orbit the sun?

365

how can you find orbital speed?

(2 x π x orbital radius) / time period

what is the colour of a live wire?

brown

what is the colour of an earth wire?

green and yellow

what is the colour of a neutral wire?

blue

what is the 1st pin on a plug?

live wire

what is the 2nd pin on a plug?

earth wire

what is the 3rd pin on a plug?

neutral wire

what are the pins in a plug made of?

brass

what are the cables made of in a plug?

copper

what is the case, cable grip and cable insulation made of?

plastic

what is the voltage of a neutral wire?

0

what is meant by the term double insulated?

when the appliance has metal casing and no metal parts showing

what happens to a fuse when the current is too high?

it blows (and the circuit breaks)

what does an earth wire do?

takes the current to the earth

what happens to current when the resistance increases?

current decreases

what is electrical power?

rate of transfer of energy

what is power measured in?

watts

give the equation linking electrical power, current and voltage

electrical power=current x voltage

give the equation linking energy transferred, time, current and voltage

energy transferred=current x voltage x time

what is current?

rate of flow of charge

what is resistance?

anything in the circuit that slows the flow down

what is the unit of resistance?

ohm

what happens to current when the voltage increases

it increases

what is this symbol?

ammeter

what is this symbol?

cell

what is this symbol?

battery

what is this symbol?

what type of current is this?

power supply, DC

what is this symbol?

what type of current is this?

power supply, AC

what is this symbol?

earth

what is this symbol?

fuse

what is this symbol?

transformer

what is this symbol?

filament lamp

what is this symbol?

LED

what is this symbol?

loudspeaker

what is this symbol?

microphone

what is this symbol?

electric bell

what is this symbol?

motor

what is this symbol?

fixed resistor

what is this symbol?

variable resistor

what is this symbol?

diode

what is this symbol?

LDR

what is this symbol?

thermistor

what type of current is in a mains supply?

AC

what type of current is in a battery supply?

DC

what is AC?

alternating current (current is always changing direction)

what is DC?

direct current (current always goes in the same direction)

give the equation linking voltage, current and resistance

voltage=current x resistance

what component is this for?

filament lamp

what component is this for?

wire