The Science of Physics

Fundamental Units

SI Standards

Units	Standard	Unit Symbol
Meter (length)	distance traveled by light in a vacuum in s	m
Kilogram (mass)	mass of a specific platinum-iridium alloy cylinder	kg
Second (time)	9192631700 times the period of a radio wave emitted from a cesium-133 atom	s

Derived Units-combination of fundamental units, for example velocity is meters/second.

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Factor	Prefix	Symbol
	yotta-	Y
	zetta-	Z
	exa-	E
	peta-	P
	tera-	T
	giga-	G
	mega-	M
	kilo-	k
	hecto-	h
	deka-	da
	deci-	d
	centi-	c
	milli-	m
	micro-	µ
	nano-	n
	pico-	p
	femto-	f
	atto-	a
	zepto-	z
	yocto-	y

The prefix's in bold are the most common in Physics Class.

 

Changing Measurements (Factor Label Method)

Example 1
The research submersible vessel ALVIN is diving at a speed of 36.5 fathoms per minute.
(a) Express this speed in meters per second. A fathom (fath) is precisely 6 ft.

 

(b) What is this speed in miles per hour?

 

 

Example 2
How many square meters are in an area of ?

 

 

Dimensional Analysis

Dimensions of Some Common Physical Quantities
Quantity	Dimension
Distance
Area
Volume
Velocity
Acceleration
Energy

Example 3
Show that is dimensionally consistent. The quantities x and are distances, is a velocity, and a is an acceleration.

 

 

 

Four Fundamental Forces

The Four Fundamental Forces
Force	Couples with	Strength	Range
Strong	Quarks and Particles composed of them
Electromagnetic	Electrically charged particles		Unlimited
Weak	Most Particles
Gravitational	All particles		Unlimited

 

Significant Digits

Rules for determining whether zeros are significant figures

1. Zeros between other nonzero digits are significant.

2. Zeros in front of nonzero digits are not significant.

3. Zeros that are at the end of a number and also to the right of the decimal point are significant.

4. Zeros at the end of a number but to the left of a decimal are significant if they have been measured or are the first estimated digit; otherwise, they are not significant.

Rules for calculating with significant figures

Type of Calculation	Rule
Addition or Subtraction	The final answer should have the same number of digits to the right of the decimal as the measurement with the smallest number of digits to the right of the decimal.
Multiplication or Division	The final answer has the same number of significant figures as the measurement having the smallest number of significant figures.

 

Mathematics in Physics

In Physics we use many different areas of mathematics, from simple addition and subtractions to derivatives and integrals. Most of the math starts with data and graphs.

 

 

 

 

 

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