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!