GCSE Edexcel Physics Paper 1

define vector

quantise with magnitude and direction

List some vectors (6)

force, velocity, displacement, weight, acceleration, momentum

define scalar

quantities with magnitude but no direction

list some scalar quantities (6)

speed, distance, mass, energy, temperature, time

define velocity

speed in a given direction

distance =

s x t

walking speed =

1.4m/s

running speed =

3m/s

cycling speed=

5.5m/s

cars in towns speed

13m/s

cars on motorway speed

31m/s

trains speed

(up to) 55m/s

wind speed

5-20m/s

speed of sound in air

340m/s

define acceleration

change in velocity in a certain length of time

acceleration =

(v-u)/t

what causes acceleration of all objects in freefall to be equal

gravity

accelerate due to gravity =

10m/s/s

uniform acceleration =

v2-u2=2xaxx

gradient on distance time graph =

speed

average speed =

total distance/time

gradient of velocity time graph =

acceleration

area under velocity/time graph =

distance

Newton's first law

a force is needed to change motion

If the resultant force on a stationary object is zero

object will remain stationary

if resultant force on an moving object is zero

it will continue to move at the same speed

five forms of an acceleration

starting, stopping, speeding up, slowing down, changing direction

the larger the resultant force on an object

the more it accelerates

relationship between force and acceleration

directly proportional

force =

massxacceleration

Newton's second law

f=mxa

safety features in cars designed to increase collision time to reduce force are

seatbelt, airbags, crumple zones

how does a vehicle skid (brakes)

brakes do work on wheels, energy transferred from kinetic to thermal stores, brakes overheat

define mass

amount of stuff in an object

define weight

the force acting on an object due to gravity (caused by the gravitational field)

unit of weight

newtons

what is the single point where the force of weight acts on an object called

centre of mass

weight =

mass x gravitational field strength

If an object is travelling in a circle

constantly changing direction and velocity so must be accelerating

name of the force which keeps something moving in a circle

centripetal force

define inertia

tendency for motion to remain unchanged

inertial mass (measures how difficult it is to change somethings velocity) =

f/a

Newton's third law

reaction forces are equal and opposite

define momentum

how much oomph something has

momentum (p) =

mass x velocity

name for momentum before = momentum after

conservation of momentum

force 2 =

change in momentum / time

stopping distance =

thinking distance + braking distance

thinking distance =

distance travelled in driver's reaction time

2 factors affecting thinking distance

reaction time, speed

4 things that can affect thinking time

tiredness, alcohol, drugs, distractions

4 factors affecting braking distance

speed, mass, condition of brakes, friction (between tyres and road)

typical reaction time

1s

stopping distance for 30mph

23m

stopping distance for 60mph

53m

stopping distance for 70mph

96m

if speed doubles, braking distance increases by

a factor of 4 (squared)

f x d =

0.5xmxv2

describe kinetic energy store

moving

describe thermal energy store

the hotter an object, the more energy

describe chemical energy store

energy released by chemical reactions

describe gravitational potential energy store

in a gravitational field

describe elastic potential energy store

stretched

describe electrostatic energy store

two charges

describe magnetic energy store

two magnets

describe nuclear energy store

atomic nuclei

kinetic energy =

0.5 x mass x (speed)2

Gravitational potential energy =

mass x field strength x change in height

3 things that can happen to energy

transferred, stored, dissipated

the total energy in a closed system

has no net change

define closed system

a collection of objects that can b treated completely on its own without energy being transferred to or from the surroundings

4 ways to transfer energy

mechanically, thermally, by radiation, electrically

describe mechanical energy transfer

a force acting on an object

describe electrical energy transfer

a charge doing work against resistance

describe radiation energy transfer

(energy transferred) by waves

Energy is only useful when transferred to a

useful store

describe dissipated

energy is spread out ('lost')

efficiency =

useful energy output/ total energy input

ways to reduce wasted energy

lubrication, thermal insulation

describe conduction

when one side of an object is heated, the particles vibrate and collide transferring energy to the kinetic energy stores of other particles

what are cavity walls

an inner and outer layer of wall with an air gap in-between

three main fossil fuels

coal, oil, (natural) gas

why are fossil fuels reliable

plenty of fuel, can respond to meet changes in demand, can store fuel

advantages of fossil fuels

reliable, cheap to extract

5 renewable sources of energy

biomass, solar, wind, tidal, hydroelectricity

advantages of biomass fuel

carbon neutral, reliable (crops take a short time to grow), can be stored

disadvantages of biomass fuel

cannot respond to changes in demand, high cost to refine, takes resources away from food production, deforestation

advantages wind power

no pollution, low running costs

disadvantages of wind power

high initial cost, appearance, quantity, unreliable (only work in wind so can't meet demand changes)

advantages of solar cells

no pollution, no running costs, can be used anywhere

disadvantages of solar cells

high initial costs, unreliable (cannot produce at night or. change to meet demand)

advantages of hydroelectricity

no pollution, can respond to changes in demand, minimal running costs

disadvantage of hydroelectricity

impact on environment (due to flooding of habitats)

advantages of tidal barrages

no pollution, minimal running costs, tides are reliable

disadvantages of tidal barrages

appearance, affect boat access, high initial costs

reasons for move towards renewable energy

affect on environment, pressure from other countries and the public (on the government and companies so as not to lose business), cars

define amplitude

displacement from rest position to crest/trough

define wavelength

length of a full cycle

define frequency

number of complete cycles passing a certain point per s

1Hz =

1 wave per sec