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the mass of a particular cylinder of platinum-iridium
kilogram alloy kept at the International Bureau of Weights and
Measures. (not possible to be measured on atomic
scale as of yet)
added to units of measurements of fundamental units to
prefix
indicate smaller or larger units. eg g to kg, m to km,
etc.
Two terms may be added or equated only if they have the same
dimensionally consistent
units. Units may be multiplied/divided just like ordinary
algebraic variables.
also called the error. indicates the maximum difference
uncertainty
there is likely to be between the measured value and
the true value.
A description of how close a measurement is to the true
accuracy
value of the quantity measured.
Also called percent error. Fraction/percentage of error
fractional error
that can be expected in a measurement
All the digits that can be known precisely in a
significant figures
measurement, plus a last estimated digit
A method of writing or displaying numbers in terms of a
scientific notation
decimal number between 1 and 10 multiplied by a
power of 10.
accuracy: how close experimental value is to accepted
value; precision: how closely measured values agree
Accuracy vs. Precision with each other.
e.g. a cheap digital watch can be very precise by giving
time down to the second, but if it runs several minutes
slow it is not accurate.
, order of magnitude estimate a rough calculation that is off by a factor of two, ten, or more, but
may still be useful.
velocity the speed and direction of a moving object
force A push or pull exerted on an object
A quantity in physics, such as mass, volume, and time,
scalar quantity
that can be completely specified by its magnitude,
and has no direction.
vector quantity A physical measurement that has both a direction and magnitude.
measurement of size, length, temperature, etc. The "how
magnitude
big" or "how much". Scalar quantity, always positive.
change in a position of an object. Includes how far the
object moves and the direction. e.g. walking 3 km
north.
discplacement
Is NOT directly related to total distance traveled. e.g. a ball that is
thrown has a
curved path and has a larger total distance than the
total displacement or an object that returns to its
original position will have a displacement of zero even
though it has traveled some distance.
parallel vectors two vectors that have the same direction. (regardless of
magnitude)
a vector that has the same magnitude as another vector
negative of a vector
but is pointing in the opposite direction
antiparallel vector two vectors that have opposite directions (regardless of
magnitude)
the combining of vector magnitudes and directions. Can be
vector addition calculated graphically
using tip to tail method or parallelogram method. Can
be calculated algebraically by adding each vectors
x,y,z components.
resultant vector the vector sum of two or more vectors.
A vector separated into vertical and horizontal
components. the components are NOT vectors
themselves.
vector components
equations for components.
x component = (magnitude of