Physics
Short Description
Chapter 1...
Description
Physics is the foundation of all engineering and No engineer could design a at-screen at-screen TV, an technology. interplanetary spacecraft, spacecraft, or even a better
mousetrap without rst understanding the basic laws of physics. The study of physics is also an adventur adventure. e. ou ou will nd it challenging, sometimes frustrating, occasionally painful, and often richly rewarding.
Physics is the foundation of all engineering and No engineer could design a at-screen at-screen TV, an technology. interplanetary spacecraft, spacecraft, or even a better
mousetrap without rst understanding the basic laws of physics. The study of physics is also an adventur adventure. e. ou ou will nd it challenging, sometimes frustrating, occasionally painful, and often richly rewarding.
•
•
•
Physics is an experimental science. Physicists observe the phenomena of nature and try to nd patterns that relate these phenomena. These patterns patterns are called called physical theories theories or, when they are very well established and widely used, physical laws or principles.
Solving Physics Problems !" understand the concepts, but " #ust can$t solve the problems%%%%%%%&
The meaning of the word “theory” ' theory is an e(planation of natural phenomena based on observation and accepted fundamental principles.
Step 1: IDETI!" the relevant concepts
)se the physical conditions stated in the problem to help you decide which physics concepts are relevant.
"dentify the target variables of the problem.
"dentify the *nown +uantities, as stated or implied in the problem.
Step #: SET $P the problem hoose the e+uations that you$ll use to solve the
problem and decide how you$ll use them. "f appropriate, draw a s*etch of the situation described in the problem. raph paper, ruler, protractor, and compass will help you ma*e clear, useful s*etches./
0stimate what your results will be and, as appropriate, predict what the physical behavior of a system will be.
Step %: E&E'$TE the solution This is where you !do the math.&
Step (: E)*+$*TE your answer ompare your answer with your estimates,
and reconsider things if there$s a discrepancy.
"deali1ed 2odel "n physics a model is a simplied version of a physical system that would be too complicated to analy1e in full detail.
Standards and $nits Physical +uantity - 'ny number that is used to describe a physical phenomenon +uantitatively. 3hen we measure a +uantity we always compare it with some reference standard. 4uch a standard is called a unit of the +uantity. The meter is a unit of distance The second is a unit of time.
"nternational 4ystem, or 4" the abbreviation for its 5rench 7ength 8 meter name System6 International).
Time 8 second 2ass - *ilogram
)nit onsistency and onversions
'n e+uation must always be dimensionally consistent, 5or e(ample, if a body moving with constant speed travels a distance d in a time t , these +uantities are related by the e+uation d - vt
"f d is measured in meters, then the product must also be e(pressed in meters.
E.ample 1,% . . 9ow many nanoseconds does it ta*e light to travel :.;; ft in vacuum< This result is a useful +uantity to remember./ E.ample 1,( . . ' s+uare eld measuring :;;.; m by :;;.; m has an area of :.;; hectare. 'n acre has an area of "f a country lot has an area of :=.; acres, what is the area in hectares< E.ample 1,/ . 9ow many years older will you be :.;; giga second from now< 'ssume a >?@-day year./
$ncertainty and Signi0cant !igres )ncertainty is indicated by the number of
meaningful digits, or signi0cant 0gres,
3hen we calculate with very large or very small numbers, we can show signicant gures much more easily by using scienti0c notation2 sometimes called powers3of314 notation,
Vectors and Vector 'ddition
Vectors and Vector 'ddition 4calar Auantity
- a physical +uantity described by a single number Vector Auantity - has both a direction and magnitude in space
Bisplacement - change in position of a point
3e usually represent the magnitude of a vector +uantity in the case of a displacement vector, its length/ by the same letter used for the vector, but in light italic type with no arrow on top. 'n alternative notation is the vector symbol with vertical bars on both sidesC
'omponents of )ectors 2easuring a diagram oDers only very limited
accuracy, and calculations with right triangles wor* only when the two vectors are perpendicular. 4o we need a simple but general method for adding vectors. This is components.. called the method of components
o ng ec or 'alclations $sing 'omponents :. 5inding a vector$s magnitude and direction from its components.
=. 2ultiplying a vector by a scalar
>. )sing components to calculate the vector sum resultant/ of two or more vectors.
)nit Vectors ' nit vector is a vector that has a magnitude of :, with no units. "ts only purpose is to point Ethat is, to describe a direction in space.
View more...
Comments
