Physics topic 1 2 & 3

Ways energy is transferred

Mechanically

Electrically

Through heating

Via infrared radiation

Via light/sound waves

Energy stores

GPE

Light

Elastic potential

Nuclear

Thermal

Electrically

Chemically

Kinetically

Sound waves

renewable energy stores

wind

solar

biofuels

hydroelectricity

geothermal

tidal

Biofuels

Made from LIVING organisms

contrast to fossil fuels (DEAD organisms)

plants and algaea trap suns energy (photosynthesis)-energy is released when we combust the fuel

How biofuels MAY NOT be carbon neutral

Tress cut down-No co2 absorbed and may be burned = realeses co2

Energy required to harvest,process and transport biofuels=releases more co2

Newtons 1st law

Resultant force is required to change motion of an object

2nd law

if a non resultant force acts on a object,then it will cause object to accelerate = DEPENDS ON INITIAL MOTION OF OBJECT

a=v²-u² / t - any changes in direction CHANGES VELOCITY

Circular motion

motion of onject travelling in a circle

objects in circular motion is always accelerating due to CONTINUAL DIRECTION CHANGE= centripetal force IS ALWAYS REQUIRED

Centripetal force

resultant force which acts towards centre of circular path of an object circular motion

conservation of momentum

total momentum before collision = total momentum after

why does an object in circular motion have a constantly changing velocity

speed remains constant BUT direction is ALWAYS CHANGING = accleration = constantly changing velocity

inertial mass

how difficult it is to change an objects velocity

eg . large objects = lots of inertial mass (lots of force required)

Inertia

tendency for the motion of an object to remain unchanged

eg

unless acted on;qn object will stay at rest/motion

using light gates

-set up two,one at end and one start

-measure distance between them

-as soon as the object passes througth the first,it will measure the time taken to reach the second

then s=d/t

MORE ACCURATE-REMOVES REACTION TIME AND HUMAN ERROR

3rd law

when two objects interact,the forces exert on each other are equal(magnitude) and opposite (direction)

Momentum

CONSERVED

p=mv

f=mv-mu/t

ways to reduce waste energy

lubricate systems

thermal isulation

effecinecy can be increased by

reducing waste output

recycling waste output (asorbing heat dissipated and used to as input heat enrgy)