Physics year 10 mock

-Solids and Liquids have similar densities (space between particles does not change significantly but usually liquids have a lower density)

-Gases have a far lower density (spacing between atoms increases greatly because particles have lots of energy to move so volume increases greatly)

It’s conserved

Physical and reversible

not chemical - material retains it’s original properties when reversed

Energy stored by particles (atoms and molecules) within a system

Takes form of kinetic energy (vibration of atoms etc) or potential energy (between particles)

Energy particles have is increased

This increases internal energy (either raises temp of system or produces a change of state)

The amount of energy required to raise the temperature of 1kg of a substance by 1°C

change in thermal energy = mass × specific heat capacity × temperature change

The amount of energy needed to change the state of 1kg of a substance without a change in temperature

The substance needs to be at the right temperature to change state first

Specific Latent Heat of fusion is energy to melt/freeze

Specific Latent Heat of vaporisation is energy to boil/condense

Energy is absorbed when melting and evaporating and energy is released when freezing and condensing.

Solid → Gas

In constant random motion

average kinetic energy of the molecules

the greater the average kinetic energy and so the faster the average speed of the molecules

Molecules colliding with container = exert a force on wall

The total force exerted by all of the molecules inside the container on a unit area of the walls is pressure

changes the pressure exerted by the gas (known as the Pressure law)

Affects pressure

Increasing the volume in which a gas is contained (at constant temperature) = decrease in pressure (Boyle’s law)

due to the reduced number of collisions per unit area.

net force at right angles to the wall of the gas container (or any surface).

decrease in pressure

increases it’s temperature

compressing or expanding the gas, so changing the volume

-Pressure increases

-Energy transferred w/ pressure, so temp increases

-Particles collide with wall (moving inward)

-Particles gain momentum (rebound velocity faster than inward velocity)

-As particle has greater velocity, pressure increases

-Temp increases (kinetic energy increases)

An object or group of objects

When a system changes, the way energy is stored changes

-System is moving ball

-When it hits wall, some of the kinetic energy is transferred as sound

The type of energy stored in a spring when it is stretched

The energy required to raise the temperature of 1kg of a substance by 1°C or 1K.

rate at which energy is transferred or the rate at which work is done

-Energy CANNOT be created or destroyed

-It can be transferred and stored usefully or dissipated

Energy is dissipated - stored in less useful ways

Often described as being ‘wasted’

Lubrication (oil in motor → reduces friction so less energy lost as heat)

Thermal insulation (double glazing → less useful thermal energy lost)

heat is allowed to travel through the material more easily, so the higher the rate of energy transfer by conduction across the material

-Rate of cooling low IF walls are thick and thermal conductivity of walls are low

-if walls are thin metal sheets, conductivity would be lost quickly

ratio of useful work done by machine, engine etc to energy supplied to it - often expressed as a percentage

efficiency = useful energy output / total energy output

energy can be replaced with power ^

-Reducing waste output (e.g lubrication, thermal insulation)

-Recycling waste output (e.g absorbing thermal waste and recycling as input energy)

-Fossil Fuels (coal, oil, gas)

-Nuclear Fuel

- Biofuel

-Wind

-Hydro-electricity

-Geothermal

-Tidal

-Solar

-Water waves

energy which can be replenished as it’s used

used more for large-scale energy supplies due to the large energy output per kilogram of fuel

due to the finite lifetime of fossil fuels

Solar doesn’t work in bad weather or night

Wind is only intermittent.

Transport

Electricity generation

Heating

Fossil fuels involve destroying landscapes

Wind turbines can be considered an eyesore

Fossil fuels release harmful emissions

Solar, wind directly create electricity with no emissions

Industrial revolution

Easy to mine, provided a lot of energy

Technology has had to develop alot to be able to harness sources efficiently

political, social, ethical and economic considerations

Distance / Time

Rate of change of velocity

Change in Velocity / Time taken

a push or pull that acts on an object due to the interaction with another object

all forces are either non-contact or contact

v² - u² = 2as

Final Velocity - Initial Velocity = 2 x acceleration x distance

Magnitude (size) but no direction

Generally cannot be negative

Magnitude (size) and direction.

Can be represented by arrows (length / size = magnitude)

a vector quantity that means the distance travelled in a straight line from the start to the finish AND the direction of that straight line

1.5 metres per second

3 metres per second

6 metres per second

330 metres per second

25 metres per second

55 metres per second

250 metres per second

Vector quantity that is speed in a given direction

it may travel at constant speed BUT the velocity will

be constantly changing because velocity is a vector quantity that depends on speed and direction

the object is accelerating and a tangent must be drawn to find speed

DTG - Speed
VTG - Acceleration

how far an object moves

scalar quantity

includes both distance, measured in a straight line, and direction of that line

vector quantity

speed in a given direction

age, terrain, fitness, distance travelled

it’s rarely constant

Stopping distance = thinking distance (driver’s reaction time) + braking distance

greater stopping distance

vary from 0.2 to 0.9s

tiredness, distractions, drugs and alcohol

increase thinking distance

adverse road

weather conditions (icy, wet)

poor condition of vehicle (breaks, tires)

work done by friction force between breaks and wheel reduces kinetic energy of vehicle and temperature of breaks increases (thermal energy store increases)

greater breaking force required to stop vehicle in a certain distance

greater deceleration of vehicle

breaks could overheat

driver could lose control of vehicle

avg car length = 4 metres

3 cars

6 cars

9 cars

13 cars

18 cars

24 cars

-when breaking hard, large deceleration

-force felt on passangers and cars

large deceleration = large change in momentum over a short time, so a large force exerted on the object (person!)

-The Sun

-8 Planets

-Natural Satellites (moons)

-Dwarf Planets: Pluto, Ceres

-Asteroids, comets

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune

(My Very Excellent Mother Just Served Us Nachos)

Milky Way

The centre (heliocentric)

from clouds of dust and gas (nebulae) being pulled together by gravity

and then fusion reactions start

due to the balance of the gravitational collapse and the expansion due to fusion energy

Rock

Gas

Maybe due to past collisions throwing its axis off balance

Their gravitational field is so strong it attracts debris

Nebula

Protostar

Main Sequence star

Red Giant

White Dwarf

Black Dwarf

Red Super Giant

Supernova

Neutron Star/Black hole

when two light nuclei join (or “fuse”) to form a heavier nucleus.

-Big cloud of dust and gas

-Gravity pulls together dust and gas, core then becomes hot and protostar is made

-fusion reactions join together hydrogen nuclei to form a helium nucleus.

-This releases huge amounts of energy which is transferred by radiation.

-Gravity continues to pull protostar inwards: ‘gravitational collapse’

-Energy released by fusion causes an outward force: tries to make star expand

-Two forces are in equilibrium (balance each other out) and star becomes stable

e.g our sun!