Chapter 6 Flashcards
energy
exists in different forms and when something happens, it is likely be due to energy being transferred from one form to another. energy transfer is needed to enable people, computers machines and other devices to work and to enable processes and changes to occur
kinetic energy
energy of a moving object
gravitational energy
energy something gains when you lift it up, and which it loses when it falls
elastic energy
the energy of a stretched spring or elastic band (also known as strain energy)
chemical energy
energy contained in a chemical substance
nuclear energy
the energy contained within a nucleus of an atom
internal energy
the energy stored in a hot object is called internal energy . the atoms of a hot object jiggling rapidly about, they have a lot of energy
thermal heat
this is energy traveling from a hotter object to a cooler one. it is transferred by conduction, convection or radiation
other forms of energy
light and electromagnetic energy and sound energy
energy stores
-kinetic
-gravitational potential
-chemical
-nuclear
-strain
internal
energy transfers
-electrical
-thermal
-light
sound
energy being transferred
by a force: lift something, force it to move
by heating: no matter how good insulation, heat goes from hot object to cooler surroundings
By radiation: energy transferred from sun to earth, electromagnetic radiation
by electricity: an electrical current is a convenient way of transferring energy from place to place
law of conservation of energy
energy cannot be destroyed, only can change form
-the total amount of energy before and after is constant
conservation of energy in multiple stages
many processes involve several steps before energy ends up in final form
eg: chemical to electrical
energy dissipation
when energy is transferred from one to another form, energy is lost in desired form or place (it ends up being dissipated usually in form of heat, energy light and sound)
- most common waste = heat
- wasted energy can harm environment, waste limited resources and cost money
energy efficiency
when energy is transformed =some energy is wasted and transferred away from system usually in the form of heat or waves (light and sound)
efficient system
- energy is transferred and waste energy is a form usually unwanted
- is a system where most energy is going into that system is in a form wanted
- eg: LED because most electrical energy (90%) ends up as light
inefficient system
is one which most energy ends up in forms not wanted
efficiency equation
useful energy(or power) output /
energy (or total power) input
x100
gravitational potential energy calculations (g.p.e)
gravitational energy = of an object us the energy it has due to its height in the gravitational field
- object lift =increase \
- falls = decreases
G.P.E = Mass x gravity x Height
OR
WEIGHT x HEIGHT
kinetic energy equation
1/2 x mass x speed^2
k.e = 1/2mv^2
Weight si unit
Newton’s
N
