science semester exam 4 Flashcards
the study of nature
science
the study of matter and energyphysical science
physical science
anything that has mass and takes up space
matter
the ability to do work or cause change
energy
the amount of matter in an object
mass
the transfer of energy in which a force is put on an object moves in the direction of the force
work
Scientific Methoda set of steps used to solve a problem
Scientific Method
Hypothesisan educated guess made from previous observations and knowledge
Hypothesis
the amount of space an object takes up
Volume
any factor that can change in the results of an experiment
variable
technologythe application of science to help people
technology
an explanation of an event based on observations and experiment
theory
a statement that tells what happens in an event
law
temperaturethe measure of kinetic energy of the atoms in an object
temperature
the mass per unit volume of a material
density
something created to represent an idea
model
a visual display of information used to explain an idea or concept
graph
the distance an object travels over a period of time
speed
the distance and object travels over time and the objects direction
velocity
accelerationthe change of velocity of an object over time
acceleration
the acceleration of a falling object due to gravity in a vacuum
g
a property of an object based on the objects mass and velocity
momentum
any object thrown/shot through the air
projectile
a force between any objects dependent on the mass of the objects. also defined as a downward force on all objects
gravity
a push or pull on an object
force
is equal in force but opposite directions
balanced forces
a force that is greater in one direction
unbalanced forces
the sum of all forces acting on an object
net force
the force that opposes the motion between two surfaces in contact
friction
the resistance of an object to any change in its motion ( frequently talked about with Newtons 1st law of motion)
inertia
when an object falls free from air resistance
free fall
the measurement of gravitational force on an objects mass
weight
a force from the center that makes an object move in a curved or circular path
centripetal force
a device used to make work easier
machine
the rate at which work is done
power
a measure of how much work put into a machine is changed into useful work output by the machine
efficiency
a theoretical machine in which the amount of work put into a machine is equal to the amount of work you get out of the machine
ideal machine
a machines ability to make work easier by making output force greater than input force
mechanical advantage
the energy of an object due to the objects motion
kinetic energy
the energy of an object at rest or energy stored by an object
potential energy
a unit that measures the energy in food
calorie
the total energy of an object, including both kinetic (temperature) and potential(mass)
thermal energy
the production or energy from the collisions between the nuclei or atoms
nuclear fusion
the production or energy from the splitting of uranium or atoms
nuclear fission
energy sources within the earth formed from the decay of plants and animals from millions of years ago
fossil fuels
energy resources that can be produced as quickly as they are used
renewable energy resource
energy resources that are used up quicker than they can be made
non-renewable energy resources
devices that convert light energy to electricity
photovoltaic cells
formula for speed
s= d/t
formula for acceleration
a= change in velocity / time
formula for momentum
p= w x t
formula for force
f=m x a
formula for weight
w= m x g
formula for power
P= w / t
formula for work
W= f x d
formula for efficiency
Wout / Win x 100
formula for mechanical advantage
ma= Fout / Fin
SI unit measure of length
meter
SI unit measure of mass
gram
SI unit measure of volume
kiloliters
SI unit measure of density
Kg/m³
SI unit measure of time
second/ minute
SI unit measure of temperatue
kelvin
SI unit measure of speed
m/s
SI unit measure of acceleration
m/s² + direction
SI unit measure of force
Newton
SI unit measure of weight
Newton
SI unit measure of work
joules
SI unit measure of energy
joules
SI unit measure of power
watts
law of conservation of energy
energy can neither be created nor destroyed - only converted from one form of energy to another
1 inch = ____ cm
2.54 centimeters
1 meter = ____ yds
1.09 yards
1 mile = ___ km
1.61 kilometers
1 oz = ___ g
28.35 grams
1 kilogram = ___ lbs
2.2 pounds
1 liter = ___ qts
1.06 quarts
1 gallon = ____ liters
3.78 liters
Newtons 1st law
An object at rest remains at rest, and an object in motion remains in motion at constant speed and in a straight line unless acted on by an unbalanced force
Newtons 2nd law
F= m x a
Newtons 3rd law
for every action (force) in nature there is an equal and opposite reaction
how efficient are photovoltaic cells
15-20 %
how efficient is hydroelectric power
70%
how efficient are wind turbines
30-45%
how efficient is geothermal energy
12-20%
how efficient is biomass
20%
5 types of renewable energy resources
solar, hydroelectricity, wind, geothermal, biomass
what % of energy of the US is using solar
3%
what % of energy of the US is using hydroelectric
7.4%
