Science Final Flashcards
Acceleration
how speed changes over a period of time
Average speed / speed
total distance covered divided by total time taken to cover that distance
constant speed
speed that remains the same over a particular time period
instantaneous speed
speed at a particular moment
velocity
change in speed over a period of time that also involved some type of direction (mph north)
inertia
an objects ability to resist change in a state of motion
Law of Conservation of Momentum
states that momentum is always conserved in any interaction
Newtons First Law of Motion
1st LOM
an object at rest stays at rest, and an object stays in motion, Unless acted upon by an unbalanced, outside force
Newtons Second Law of Motion
2nd LOM
force = mass * acceleration (f=m*a)
Newtons Third Law of Motion
3rd LOM
for every action there is an equal and opposite reaction
Unbalanced forces
forces that cause acceleration
efficiency
the ratio of output work divided by input work, a percentage, nothing is ever 100% efficient
energy
the ability to do work
energy transfermation
energy changing from one form to another
heat
thermal energy that is moving or capable of moving
horsepower
unit of power
= to 746 watts
Joule
equal to 1 newton times 1 meter, unit of energy and work
kinetic energy
energy of motion
Law of conservation of energy
energy cannot be created or destroyed, only transferred
potential energy
energy that is stored, comes from position
gravity (g) on earth
g=9.8
power
the rate of doing work
watt
unit of power
work
force times distance or power times time, but the force applied must be in the same direction as the distance it moves
examples of work
lifting, pushing, pulling
NOT carrying or losing tug of war
atomic mass
protons + neutrons
electrons
equal to number of protons, negative charge, outside nucleus, have levels
groups
down (columns) on periodic table, valence electrons
isotopes
same element, different mass number
mass number
number of protons (or electrons)
metal
takes up most of the elements on the table, left side
neutron
in nucleus, neutral
noble gasses
column 18, full balanced shell (8), don’t react (except helium)
nonmetal
takes up right side of table
nucleus
99% of mass in an atom, made up of protons and neutrons
period
across (rows) on periodic table, energy level
periodic table
a table you use periodically (jk)
proton
positive charge, in nucleus
Chemical bond
the joining of atoms to form new
covalent bond
bond between two nonmetals , electrons are shared, (greek prefixes)
example: H2O
Ion
term used to describe an atom with a charge other then zero
ionic bond
bond between metal and nonmetal, electrons are transferred, (-ide) (no prefixes)
example: MgBr2
Lewis Dot Diagram
method used to visually represent valence electrons
Oxidation number
represents how many electrons to give or take to get full outer shell, and/or what the most likely charge on an atom will be (electrons are lost, gained or shared)
valence electrons
number of electrons in outer shell, determine how atoms react, involved in chemical bonding
addition (synthesis) reaction
2 elements combine to make a compound
example: 2Na+Cl2–>2NaCl
chemical change
a change that results in a new substance being formed
chemical equation
short hand way to show chemical reaction
example: H2+O2–>H2O
coefficient
number put in front of a chemical formula to balance it
examples in chapter 17 packet
combustion reaction
reaction in which CO2 + H2O + energy is produced
decomposition reaction
a compound breaking down into 2 or more elements
example: H2CO3–>H2O+CO2
double displacement (replacment) reaction
an element in 2 different compounds switch places
example: NaCl + AgF –> NaF + AgCl
formula mass
found by combining the individual mass of each atom in a compound
physical change
a change that does not result in a new substance being formed
product
what is formed in chemical reaction, right side of arrow
reactant
what takes part in chemical reaction, left side of arrow
single displacement replacment) reaction
an element replaces another element in compound
example: Zn +2HCl –> ZnCl2 + H2
fulcrum
Glodek said this is 10/10 important
stiff structure that separates the input force and output force (needed for all levers)
gears
rotating wheel with teeth that transfers motion forces to other gears or objects
input
force energy or power supplied to make a machine accomplish a task
input arm
side of lever in which input force is applied
input force
force that is applied to a machine
lever
stiff structure that rotates around a fixed point (3 classes of levers
1st class lever
fulcrum is right in the middle of output and input (OFI), output force is equal to input force (O=I) , ex: a see-saw
2nd class lever
fulcrum then output then input (FOI), output force is greater then input force (O>I), ex: a wheelbarrow or door
3rd class lever
fulcrum then input then output (FIO), output force is less then input force (I>O), ex: your arm, jaw, or a broom
machine
a devise with moving parts that work together to complete a task
mechanical advantage (Glodek said this is very very important)
ratio of output force divided by input force (O/I)
output
forces energy or power provided by machine
output force
force that is produced by a machine
pulley
a simple machine that can increase force by changing direction
simple machine
unpowered mechanical device that accomplishes a task with 1 step or motion
amplitude
the amount that a cycle moves away from equilibrium
cycle
one repetition of motion
frequency
how often something repeats, expressed in hertz
harmonic motion
motion that repeats in cycles
hertz
unit of frequency, 1 hertz = 1 cycle per second
linear motion
motion that goes from one place to another without repeating
natural motion
the frequency at which a system vibrates when it is disturbed
oscillator
physical system that has repeating cycles
period
the time it takes to complete one cycle
periodic force
repetitive force
resonance
an exceptionally large amplitude that develops when a periodic force is applied to a natural frequency
restoring force
force that acts to pull a system back to equilibrium
wavelength
distance from crest to crest to trough to trough of any wave
Acceleration formula
(final speed - starting speed)/ time
Speed and velocity formula
speed=distance/time
momentum formula
mass * velocity
force formula
force = mass * acceleration (f=m*a)
efficiency formula
work output /work input (will equal a decimal)
kinetic energy formula
(1/2) mass * velocity squared
Ek=(m*v^2)/2
potential energy formula
mass* gravity (9.8)*height
Ep= mgh
work formula
forcedistance (w=fd)
powertime (w=pt)
mechanical advantage formula
output force/ input force
mechanical advantage of a lever when given the arms formula
input arm /output arm
density
mass/volume
dependent variable
what is measured from experiment, plotted on Y axis
direct relationship
increase in 1 variable and produces same increase in another variable
gram
metric unit of mass
graph
shows how variables relate
independent variables
the one variable that is changes in experiment, plotted on X axis
inverse relationship
increase in 1 variable produces decrease in another variable
kilogram
=1,000 grams, basic unit of mass in metric system
mass
amount of matter
scatterplot
graph that shows relationship between 2 variables
volume
amount of space an object takes up
weight
depends on mass and gravity, Not the same as mass
Kinetic energy increases with:
mass and speed.
Efficiency is defined as the ratio of:
work output to work input.
When constructing a graph, the x-axis is most closely related to:
the independent variable.
The “building blocks” of matter are:
atoms and molecules.
The inertia of an object is related to its:
mass only.
The second row of the periodic table has 8 elements because:
the second energy level can hold 8 electrons.
If you go twice as fast, your kinetic energy becomes:
4 times bigger.
Batteries are devices that change chemical energy to ____ energy.
electrical
The rate at which velocity changes is called:
acceleration.
The density of a liquid is higher than the density of a gas because:
particles of a liquid are closer together than particles of a gas.
Newton’s first law of motion is also known as:
the law of inertia.
The variable usually represented on the x-axis is the ____ variable.
independent
A scatterplot is the best type of graph to use when:
one variable causes a second variable to change in value.
In order for evidence to be considered scientific evidence, it must be:
objective and repeatable.
Compared to protons, electrons have:
much smaller mass and opposite charge.
Atomic number is:
the number of particles in an atom.
what are the horizontal rows on the periodic table called?
periods
what are the vertical rows on the periodic table called
groups or families
A unit used to measure the period of a cycle is the:
second.
An object at rest has:
inertia but no momentum.
If the mechanical advantage of a simple machine is 5, then:
the output force is 5 times greater than the input force.
A longitudinal wave travels:
in the same direction as the oscillations.
The amount of time required for one cycle to occur is called the:
period.
Which of the following use the same units of measurement?
Energy and work
Kinetic energy increases with:
mass and speed
energy can be considered stored:
work
simple machine can multiply
force and speed
