Full class meets 2 times per week in FL2-208 MW 5:30–6:50 PM

▪ Lectures▪ PowerPoint presentations▪ Lecture materials will be made available on the web

▪ Work out example problems and questions▪ Demonstrations

Laboratory section meets twice a week following lecture MW 7:00–8:20 PM: FL2-208

▪ Opportunity for discussions on course material, exam prep, etc.

Your Fellow Students! Encouraged to work together on homework,

exercises (but not on exams!) Tutoring: Tutoring center located in Aspen Hall

room FL1-108 or the Reading, Writing, and Math Center at Cypress Hall FL2-239

Instructor! Office in FL2-208, office hours F 4:00 PM – 5:00 PM,

or by appointment mondays@flc.losrios.edu

Web: flc.losrios.edu/~mondays Lecture presentations, updates, HW

assignments/solutions Text

Physics, Sixth Edition, Giancoli

1. Explore the approach that physics brings to bear on the world around us

Scientific Method Quantitative Models Reductionism

2. Appreciate the influence physics has on us all

Begin to see physics in the world around you

Develop your natural intuition, stimulate curiosity

Think into the unknown (ooh that’s scary!)3. Understand basic laws of physics

Newton’s laws of motion, gravitation Concepts of mass, force, acceleration,

energy, momentum, power, etc. Fluid mechanics, mechanical waves

(including sound), and thermodynamics.

Science is as much about questions as answers. You may have questions about:

▪ Something you’ve always wondered about▪ Something you recently noticed▪ Something that class prompted you to think about

Goal is to increase your awareness, observational skills, analytical skills▪ We’re immersed in physics: easy to ignore, but

also easy to see!▪ You’ll begin to think more deeply before shoving

problem aside▪ Allow your natural curiosity to come alive

Attend lectures and laboratory section Participate!

If it doesn’t make sense, ask! Everyone learns that way.

Don’t be bashful about answering questions posed.

Do the work: It’s the only way this stuff will really sink in exams become easier

Explore, think, ask, speculate, admire, enjoy! Physics can be fun

• No one who came more than 80% of time did very poorly• Few who came infrequently got more than a low B

An attempt to rationalize the observed Universe in terms of irreducible basic constituents or simplest form, interacting via basic forces. Reductionism!

An evolving set of (sometimes contradictory!) organizing principles, theories, that are subjected to experimental tests.

This has been going on for a long time.... with considerable success

Attempt to find unifying principles and properties e.g., gravitation:

Kepler’s laws of planetary motion

Falling apples

Universal Gravitation

“Unification” of forces

Physics is always on the move theories that long stood up to experiment

are shot down But usually old theory is good enough to

describe all experiments predating the new trouble-making experiment otherwise it would never have been adopted

as a theory Ever higher precision pushes incomplete

theories to their breaking points Result is enhanced understanding

deeper appreciation/insight

PhysicalReality

OurUniverse

Engineering

Geology

Astronomy

Biology

Chemistry

Abstraction

First Up – ReviewNext Lectures – KinematicsAssignments:

Check out course web page:▪ flc.losrios.edu/~mondays

Reading:▪ Giancoli, Chapter 1

Units Any measurement or quantitative

statement requires a standard to compare with to determine its quantity▪ If I go a speed of 30, how fast am I going?

▪ Mi/hr. km/hr, ft/sec

Units help us to quantify against a known standard

Basis of testing theories in scienceNeed to have consistent systems of

units for the measurementsUncertainties are inherentNeed rules for dealing with the

uncertainties

Standardized systems agreed upon by some authority, usually

a governmental bodySI -- Systéme International

agreed to in 1960 by an international committee

main system used in this course also called mks for the first letters in the

units of the fundamental quantities

cgs -- Gaussian system named for the first letters of the units it

uses for fundamental quantitiesUS Customary

everyday units (ft, etc.) often uses weight, in pounds, instead of

mass as a fundamental quantity

Three basic quantitative measurements Length Mass Time

All units can be reduced to these three units!

Units SI -- meter, m cgs -- centimeter, cm US Customary -- foot, ft

Defined in terms of a meter -- the distance traveled by light in a vacuum during a given time (1/299 792 458 s)

Units SI -- kilogram, kg cgs -- gram, g USC -- slug, slug

Defined in terms of kilogram, based on a specific Pt-Ir cylinder kept at the International Bureau of Standards

Units seconds, s in all three systems

Defined in terms of the oscillation of radiation from a cesium atom

(9 192 631 700 times frequency of light emitted)

Dimension denotes the physical nature of a quantity

Technique to check the correctness of an equation

Dimensions (length, mass, time, combinations) can be treated as algebraic quantities add, subtract, multiply, divide quantities added/subtracted only if have same

units Both sides of equation must have the same

dimensions

Dimensions for commonly used quantities

Length L m (SI)Area L2 m2 (SI)Volume L3 m3 (SI) Velocity (speed) L/T m/s (SI)Acceleration L/T2 m/s2 (SI)

Example of dimensional analysis Example of dimensional analysis

distance = velocity · time L = (L/T) · T

When units are not consistent, you may need to convert to appropriate ones

Units can be treated like algebraic quantities that can cancel each other out

1 mile = 1609 m = 1.609 km 1 ft = 0.3048 m = 30.48 cm1m = 39.37 in = 3.281 ft 1 in = 0.0254 m = 2.54 cm

Example 2Example 2. Trip to Canada:. Trip to Canada:Legal freeway speed limit in Canada is 100 km/h.

What is it in miles/h?

h

miles

km

mile

h

km

h

km62

609.1

1100100

Prefixes correspond to powers of 10 Each prefix has a specific name/abbreviation

Power Prefix Abbrev.

1015 peta P109 giga G106 mega M103 kilo k10-2 centi P10-3 milli m10-6 micro 10-9 nano n

Distance from Earth to nearest star 40 PmMean radius of Earth 6 MmLength of a housefly 5 mmSize of living cells 10 mSize of an atom 0.1 nm

Example: An aspirin tablet contains 325 mg of acetylsalicylic acid. Express this mass in grams.

Solution:Given:

m = 325 mg

Find:

m (grams)=?

Recall that prefix “milli” implies 10-3, so

There is uncertainty in every measurement, this uncertainty carries over through the calculations need a technique to account for this

uncertaintyWe will use rules for significant

figures to approximate the uncertainty in results of calculations

A significant figure is one that is reliably known All non-zero digits are significant Zeros are significant when

between other non-zero digits after the decimal point and another significant

figure can be clarified by using scientific notation

4

4

4

1074000.10.17400

107400.1.17400

1074.117400

3 significant figures

5 significant figures

6 significant figures

Accuracy -- number of significant figures

When multiplying or dividing, round the result to the same accuracy as the least accurate measurement

When adding or subtracting, round the result to the smallest number of decimal places of any term in the sum

Example: 135 m + 6.213 m = 141 m

meter stick: cm1.0

rectangular plate: 4.5 cm by 7.3 cmarea: 32.85 cm2 33 cm2

2 significant figures

Example:

Example:

Approximation based on a number of assumptions may need to modify assumptions if more precise results

are needed

Order of magnitude is the power of 10 that appliesExample: John has 3 apples, Jane has 5 apples. Their numbers of apples are “of the same order of magnitude”

Question: McDonald’s sells about 250 million packages of fries every year. Placed end-to-end, how far would the fries reach?

Solution: There are approximately 30 fries/package, thus:

(30 fries/package)(250 . 106 packages)(3 in./fry) ~ 2 . 1010 in ~ 5 . 108 m,which is greater then Earth-Moon distance (4 . 108 m)!

sin

sideadjacent

sideopposite

hypotenuse

sideadjacent

hypotenuse

sideopposite

tan

cos

sin

Pythagorean Pythagorean TheoremTheorem

Slide 13

Fig. 1.7, p.14

Known: angle and one sideFind: another side

mmdistheight

dist

buildingofheight

3.37)0.46)(0.39(tantan.

,.

tan

Key: tangent is defined via two sides!

Used to describe the position of a point in space

Coordinate system (frame) consists of a fixed reference point called the origin specific axes with scales and labels instructions on how to label a point

relative to the origin and the axes

Cartesian Plane polarSpherical Cylindrical

also called rectangular coordinate system

x- and y- axes points are labeled

(x,y)

origin and reference line are noted

point is distance r from the origin in the direction of angle , ccw from reference line

points are labeled (r,)

Looking at the figure, we can see that

leading to the relationship

This is how you would change polar coordinates to rectangular coordinates.

r

xcos

r

ysin

cosrx sinry

Looking at the figure, we can also see that

This is how you would change rectangular coordinates to polar coordinates.

222 yxr x

ytan

x

y1tan

Find the rectangular coordinates of the point P whose polar coordinates are (6, 2/3).

Find the rectangular coordinates of the point P whose polar coordinates are (6, 2/3).

Since r = 6 and = 2/3, we have)cos(6 3

2x )sin(6 32y

3

)(6 21

x

x

33

)(6 23

y

y