g

Thinking distance

Distance a vehicle travels in the time between a driver realising they need to stop and applying the brakes

Braking distance

The distance a vehicle travels after the driver applies the brakes

Stopping distance

thinking distance + braking distance

The thinking distance could be affected by…

Tiredness, too much drug/alcohol use, distractions or poor visibility

The braking distance could be affected by…

Wet or icy roads, poor vehicle conditions or driving too fast.

Electromagnetic waves are _____ waves that travel at the same speed (or velocity) in a ______

Transverse, vacuum

What is the EM spectrum in order of ascending frequency?

Radiowaves, microwaves, infrared radiation, visible light, ultraviolet, xrays, gamma rays

What does ROYGBIV stand for?

The colours in the visible light spectrum

Gamma waves have the shortest ________ and the highest frequency, thus meaning that they have the most ____

Wavelength, energy

What type of electromagnetic wave has the longest wavelength and lowest frequency?

Radiowaves

As the wave frequency increases, so does the…

Wave energy

As the wavelength increases…

The wave energy decreases

What is momentum?

the product of an object’s mass and its velocity.

Momentum is a _____ quantity (it has magnitude and direction)

Vector

What is the conservation of momentum principle?

Total momentum before event = total momentum after event (in a closed system)

Equation for momentum

P = m x v

m is mass

v is velocity

A car with a mass of 1200kg is travelling at 15m/s, calculate its momentum.

1200 × 15 =18 000 Kg m/s

What is momentum measured in?

Kg m/s

Why do airbags reduce injury in a crash (in terms of momentum)?

Airbags increase the time taken for the change in momentum, which reduces the force on the person.

Force equation

force = change in momentum/ time

Why is momentum conserved in an explosion?

The total momentum before the explosion equals the total momentum after the explosion.

What is meant by a scalar quantity?

a quantity that has magnitude only and no direction.

What is meant by a vector quantity?

a quantity that has magnitude and direction.

Convert 6 kJ to mJ

6000000 mJ

Convert 20Kg to grams

20000g

Convert 15g to mg

15000 mg

Convert 100 mJ to kJ

0.00001

System

An object or group of objects we are interested in

A _____ is an object or group of objects we are interested in

System

What are the three main types of system?

Open, closed, isolated

What is matter?

Anything in the universe that occupies space and has mass

In an open system…

Both matter and energy can either enter or exit

In an isolated system…

Neither matter or energy can enter or leave

In a closed system…

Matter cannot enter or leave but energy can

Give an example of a closed system

A flask filled with water

Give an example of an open system

Boiling eggs in a saucepan

Force

A push or pull, measured in newtons (N)

A force is a __1__ or pull, measured in __2__

1= push, 2= newtons

Work

The measure of energy transfer when a force moves an object through distance

____ is the measure of energy ____ when a force moves an object through _____.

Work, transferred, distance

Energy transferred =

Work done

Energy transferred is measured in…

Joules

How do we calculate work done?

Force x Distance

How do we calculate efficiency?

Useful power output / total power input

What is efficiency?

A measure of how well a device transfers energy into useful forms rather than wasting it

No device can be 100% efficient, why is this?

Energy is often dissipated as heat

wavelength

distance between crests of a wave

crest

top of wave

trough

bottom of wave

amplitude

height of wave

wavelength

distance between 2 waves

equilibrium

point of wave on the line

frequency

waves passing through a given point

velocity

speed & direction of propagation

electromagnetic spectrum

range of energies w/ distinct wavelengths and frequencies

energy

frequency of wave

radiation

emission/transmission of energy in the form of electromagnetic waves through space/medium

ionized = not safe

not ionized = safe

mechanical waves

transversal & longitudal

includes sound

increased wavelength

decreased frequency & energy

decreased wavelength

increased frequency & energy`

What is refraction?

When light travels from one medium to another and changes speed

Refraction is where light travels from one medium to another and changes ____

Speed

What is the law of reflection?

Angle of incidence = angle of reflection

What is the normal?

A line at 90 degrees from the plane (flat surface)

What is the angle of incidence?

The angle between the incident (incoming) light ray and the normal

What is the angle of reflection?

The angle between the reflected light rat and the normal

What is the angle of refraction?

The angle between the refracted light rat and the normal

If light slows down when it enters a new medium, the medium is considered…

Optically dense

When light enters a more optically dense medium, it is refracted _____ to the normal

Closer

If a light rat enters an optically dense medium, will the angle of refraction be smaller or greater than the angle of incidence?

Smaller

If a light rat enters a less optically dense medium, will the angle of refraction be smaller or greater than the angle of incidence?

greater

Light will speed up when entering a ____ optically dense medium

Less

What does label A stand for?

The normal

What is the resolution of a protractor?

1 degree

What does label B stand for?

The incident ray

What does label C stand for?

The incident angel

What does label D stand for?

The refracted ray

What does label E stand for?

The angle of refraction

Glass has a _____ refractive index than air

Higher

How can you detect latent heat?

Use a joule-meter and measuring the energy supplied to change state

A transformer can change the voltage (potential ______) in wires carrying _____ currents

Difference, currents

The _____ of a body is a measure of the energy in the _____ stores of its _____

Internal, kinetic, particles

What are the two components of an objects internal energy store?

Kinetic store and potential store

How does the thickness of the wire in the primary and secondary coils relate the currents they carry?

Directly proportional- thicker wire is used for larger currents to reduce resistance and prevent overheating

In an ideal transformer, the power output and input are…

Equal

Why cant transformers work with direct current?

DC doesn’t induce a changing magnetic field

What voltage is electricity transmitted over long distances?

400000V

Why isnt DC used in the national grid?

DC does not work with transformers, this is because the secondary coil of a transformer needs to be linked with an alternating magnetic field- only AC can achieve thisz

What is a moment?

The turning affect of a force

M =

F x d

What does F stand for in M = Fxd

Force

What are moments measured in

Nm

What does d stand for in M = Fxd?

The perpendicular distance from the line of action of force to the pivot

For an object to be balanced on a pivot…

The clockwise and anticlockwise moments must be equal

If the size of the anticlockwise moment is bigger than the clockwise moment on a seesaw…

The seesaw is going to pivot in an anticlockwise direction

diagram to work out line of force & using it in equation

What do oscilloscopes display?

The wave forms of different sounds

What two features of soundwaves do an oscilloscope and microphone allow us to see?

• amplitude & frequency

What do we use to produce a soundwave with a pure tone and KNOWN frequency?

A tuning fork