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Introduction Click to continue
Intro toMechanics is the port of entry into physics. A job well donein mechanics will form a solid foundation for the rest of the
subject.
NOTE
Symbols and units
Symbols are letters used in formulas.
Units are letters used in quantities.
Do not confuse symbols with units.CAUTION
m represents masst represents timeF represents forcev represents velocityW represents work
etc. etc.
Here are some examples
kg kilograms for mass s seconds for timeN newtons for forcem/s meters/second for velocityJ joules for workm meters for length
etc. etc.
Here are some examples
Look! Some
units use
capital letters
amF
tv
a
xSing a
20 kg22.5 s400 N-200 J
Note that you will need to memorizethe units because they are standard
and cannot be changed and theyare mandated by law.
MassTimeForceEnergy
It is the unit that identifies what the quantiy represents.
2i
2f v va2 s
d
Note that we can change symbols at any time and use whatever symbols we like.
For example
Introduction Click to continueClick to next slide
BASIC QUANTITIES
There are three basic quantities in mechanics.
Length
Mass
Time
UNITmeter
kilogram
second
All other quantities in mechanics are derived from these basic three and are
known as “derived” quantities.
NOTE
Remember:Only these units are allowedin physics formulas! It is yourresponsibility to convert allquantities into basic units!
Form
ulas
Form
ulas
Formulas
Hypotenuse is doubleopposite side
While the value for g is 9.8 m/s2, for quick practice,you may use 10 m/s2 to simplify your calculations.While the value for g is 9.8 m/s2, for quick practice,you may use 10 m/s2 to simplify your calculations.
From a past physics exam
NOTE
… and good luck!