Welcome to Physics 1050

Welcome to Physics 1050

Concepts of Physics

What’s the Point?

• Physics is basic

• Physics explains things

• Physics is the secrets of the universe

Who are You?

• Please clearly write your first and last name on the tent card

• Please bring your tent card to every class

Your Name

First Last

Group Work

Introduce yourself to your group.

Identify something memorable about• yourself• your home town• your family• your name• or anything else associated with you

Tell your group and write it down.

Mechanics of the Course

Standards-based grading

• Scored on standards, not points

• The more standards you meet, the higher your final grade

Meeting the Standards

• Last assessment matters

• Don’t blow off early assessments: learn!

• If lots of folks miss a standard, I’ll re-quiz

• If you personally miss a standard:– Work some more problems– See me for a re-assessment

• I want you to succeed.

Quizzes

• In lecture• May be announced or unannounced• Assess on standards (no numeric score)

Exams

• On-line– Moodle course management system– Thursday Evenings– Awarded points aren’t directly significant

• Final – Last opportunity to make up missed standards

• Evaluate on standards

Textbook

• Textbook; Hewitt, Conceptual Physics 11 ed. (req.)with Practicing Physics workbook

• Lab manual: photocopy(also online)

LabPhysical Science building room 137

(north hallway)

Hours: TW 1:10–3:00

Labs begin

TODAYTA’s:• We’re still working on that

Discussion Section

Times and locations vary

Discussions begin

TODAY

TAs: TBA

Hours: T 11:00–11:50

3:10–4:00R 3:10–4:00

PollEverywhere

Poll input by text message, web site, or Twitter.

Which is best?

• A good thing.

• A bad thing.

How to Succeed

Read the Textbook

• Read before class

• Study after

• Reading guides available on web site

Prepare for Lab

• Read manual before lab

• Lab manual on class web site

• Pre-labs due in lab

Use Web Resources

• Class web site – www.barransclass.com/phys1050– Syllabus, schedule, lab manual, reading

guides, highlights, PowerPoints,etc.

• Moodle– CRTeacher2.com– Practice problems: practice all you want– Register on-line immediately

Visit Me

Physical Science building room 110

(south hallway)

Hours: MWF 3:10–4:00 PMR 11:00–11:50 AM

or by appointment

or come in if the door is open

33% more

Free!

Absence Policy

• Contact me beforehand if foreseen• Contact me ASAP for emergencies• Arrange make-up within one week of

return• No make-up or re-take for items missed

without approval• Labs pro-rated if make-up impractical

Pre-Vet, Pre-Dent

• Many grad schools require PHYS 1110

• UW grants credit for only one of PHYS 1050, 1110, 1210

• FWIW: Students taking 1110 after 1050 tend to do very well

• I provide a guarantee

The Science of Physics

The fundamental quantities

Indefinable Fundamentals

• Distance

• Mass

• Electric charge

• Time

Distance

• Defined circularly with length– Length: the distance between specified

locations– Distance: the length of a line segment joining

two points

American Heritage Dictionary, 1981.

Mass

6. The measure of a body’s response to acceleration. The mass of a body is different from but proportional to its weight, is independent of the body’s position but dependent on its motion with respect to other bodies, and may be expressed in mass units, such as kilograms or slugs, or corresponding energy units, by means of the mass-energy relationship of the special theory of relativity.

American Heritage Dictionary, 1981.

Charge

14a. The intrinsic property of matter responsible for all electric phenomena, in particular for the force of the electromagnetic interaction,occurring in two forms arbitrarily designated negative and positive.

American Heritage Dictionary, 1981.

Time

1. A nonspatial continuum in which events occur in apparently irreversible succession from the past to the present to the future.

2. An interval separating two points on this continuum, measured essentially by selecting a regularly occurring event, such as the sunrise, and counting the number of occurrences during the interval’s duration.

American Heritage Dictionary, 1981.

Fundamental Units

Distance meter (m)

Mass kilogram (kg)

Charge coulomb (C)

Time second (s)

SI (International System) or MKS units

Quantity Unit

Fundamental Units

• All units we will encounter are defined in terms of the fundamental m, kg, C, and s.

Working with Units

Math makes sense

Eat a live bullfrog first thing in the morning…

…and nothing worse will happen to you for the rest of the day!

Do math with units

• Unit labels can be treated like any variable in algebra.

Add them!

3 x + 4 x = 7 x

3 s + 4 s = 7 s

Multiply them!

(3a)(4b) = 12 ab

(3 m/s)(4 s) = 12 m

= 3 x/y 6 x2 y

= 3 C/s 6 C2 s

Divide them!

Compound Units

• Areas• Volumes• Accumulated effects• Effects of population

Represent:

Compound Units

a

b

Area = ab

Compound Units

3workers

Effort= (3 w) (4 h)

= 12 (w)(h)

= 12 worker·hours

4 h

Ratio Units

• Rates of change• Intrinsic properties

Represent:

Ratio Units

A baby has a mass of 3.2 kg at birth and 8.6 kg 9 months later. What is its average annual growth rate during this time?

slope =5.4 kg

0.75 y= 7.2 kg/y

mass (kg)

time (y)

10

8

6

4

2

0

0 1

0.75 y

5.4 kg

Manipulating Units

• Conversions

39.37 in = 1 m

72 in

equality

conversion factors

= 72 in · 1

=39.37 in

1 m1 =

1 m1

39.37 in

= 72 in ·1 m

39.37 in=

72

39.37m = 1.829 m

Group Work

2. 1 mi = 5280 ft1 yd = 3 ft Set up the conversion 2 mi to yd.

3. 1 mi = 5280 ft1 ft = 12 in1 m = 39.37 in1 h = 3600 sSet up the conversion 75 mi/h to m/s.

Reading for Next Time

• Distance, velocity, and acceleration: how physics describes motion

• Keep in mind the relations between different quantities

Right away

• Go to your lab session this week.

• Go to your discussion session this week.

• Get a Moodle account.

• Join this course on Moodle.

• Complete the assigned reading.