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SUMMARY OF CHPTER 1
Motion is a change in position/displacement over time. Motion can be measured by its three properties;
speed, velocity, and acceleration. Speed is a measure of how fast or how slowly an object is moving. It is
a ratio of the distance traveled divided by time. Distance and time are two examples of scalar quantities.
A scalar quantity can be completely described by a number (magnitude) and unit. Because speed is not
constant over the entire distance traveled, a most common average speed is used. Measurement in
physical sciences is so important. It consists of comparing a quantity to a standard or unit and associating
a numerical number and unit to the measured quantity. Usually, numerical values are either extremely
large or small. Scientists used scientific notation to make these numbers more readable. Contrary to
speed, velocity is a vector quantity, which requires a direction for a complete description. Acceleration is
a measure of how fast or slowly is the change in velocity (not speed). It is a vector quantity and is directed
in the direction of the change in velocity. Average values of velocity and acceleration are again more
common. Instantaneous speed is the speed at the moment, namely it is the speed at very short intervals
of times that reach, but not equal zero. Motion is either uniform or non uniform. Uniform motion is
motion on a straight line and occurs when its successive distances or displacements are equal at equal
times. Contrary to this is the non uniform motion. The metric system of measurement or its extended
version SI is the mostly used system around the world because it is based on prefixes or power of ten.
Acceleration is a measure of how fast or how slowly is the change in velocity over time. It is a vector and
points in the direction of the change in velocity. Changing units require conversion factors. A conversion
factor is a statement that relates two units. Forming a ratio of value 1 from this statement allows us to
eliminate the unwanted units and come up with the wanted unit.
Basic Equations
speed v
d
t
average speed v
d
x x f xi
, or
t
t
t
D
velocity v
t
v v f vi
accelerati on a
t
t