-The acronym SI is derived from the French Systme International.
-It is an intriguing fact that some physical quantities are more fundamental than
others and that the most fundamental physical quantities can be defined only in
terms of the p
-Zeros are significant except when they serve only as place keepers.
-On many occasions, physicists, other scientists, and engineers need to make
approximations or guesstimates for a particular quantity. What is the distance to
a certain destination
-This process typically begins with an observation and question that the scientist
-Next, the scientist typically performs some research about the topic and then
devises a hypothesis.
-Then, the scientist will test the hyp
Phenomena in Physics
-The physical universe is enormously complex in its detail. Every day, each of us
observes a great variety of objects and phenomena.
-Over the centuries, the curiosity of the human race has led us collectively to
explore and catalog a
-The SI unit for length is the meter (abbreviated m); its definition has also
changed over time to become more accurate and precise. The meter was first
defined in 1791 as 1/10,000,000 of the distance from the equator to the North
Measuring Tools and Significant Figures
-In that case, the lowest value was 10.9 in. and the highest value was 11.2 in.
Thus, the measured values deviated from each other by at most 0.3 in. These
measurements were relatively precise because they did not v
Theories In Physics
-Modern physics itself consists of the two revolutionary theories, relativity and
-These theories deal with the very fast and the very small, respectively.
-Relativity must be used whenever an object is traveling at
Dynamics of Distance
-To describe the position of a person in an airplane, for example, we use the
airplane, not the Earth, as the reference frame.
-If an object moves relative to a reference frame (for example, if a professor
moves to the ri
-Galileo was instrumental in establishing observation as the absolute determinant
of truth, rather than logical argument.
Galileos use of the telescope was his most notable achievement in
demonstrating the importance of observation.
Graphs and Dimensions
-Graphs can also be used for other topics in physics.
-An important aspect of exploring physical relationships is to graph them and look
for underlying relationships.
Vectors in Two Dimensions
-A vector is a quantity that has magnitu
Applying Problem Solving Skills
-Analytical skills and problem-solving abilities can be applied to new situations,
whereas a list of facts cannot be made long enough to contain every possible
-Such analytical skills are useful both for solvi
Unit Conversion and Dimensional Analysis
-It is often necessary to convert from one type of unit to another. For example, if
you are reading a European cookbook, some quantities may be expressed in
units of liters and you need to convert them to cups.