Course Introduction • Phy1221: Physics for Science and Engineering Students 1, Mechanics • lots of information on course web page: http://www.atsweb.neu.edu/physics/j.sage/wint00 • Lectures: Mon & Wed, 9:15-10:20, 108 SN • Lecturer: Darien Wood, 227 Dana, x2958, [email protected] • Section instructors: – Ram Bhattacharya, 353 Dana, x4209, email TBA – Clive Perry, 101 Dana, x2913, [email protected] – Tim Sage, 106 Dana, x2908, [email protected] • Problem Solving Sessions (listed as “labs”), 5 sections – Fri 8:00-10:20 (R.B.), 17 SL, Sec 5 – Fri 10:30-12:50 (C.P.), 31 SL, Sec 4 – Fri 1:00-3:20: (R.B.), 17 SL, Sec 3; (C.P.) 33 SL, Sec 2; (T.S.)13 SL, Sec 1 Lecture 1, 1/10/00

Phy1223 Fall 99

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Course Introduction (cont.) • Sequence for a typical week – Monday: finish assigned reading and take reading quiz on Webassign (by 9:15 AM) – Monday: first lecture on the week’s topic – (Tuesday: post-class assignment from pervious week due at 4:00 PM) – Wed: second (last) lecture on the week’s topic – Wed-Fri: attempt assigned common problems on Webassign (before Friday class) – Friday: work with others on common problems in Problem Solving Session, take in-class quiz – Friday-Tues: Do individual problems Webassign (same as common problems but with different numbers) before Tues 4:00 PM Lecture 1, 1/10/00

Phy1223 Fall 99

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1

Course Introduction (cont.) • The week visually Mon

( Tue

Wed

Webassign deadlines) Thu

Fri

Mon

Tues

Reading Quiz Lecutures Pre-Class hw PSS (w/ Quiz) Post-Class hw

Red: current week’s material, Green:previous, Blue: next Lecture 1, 1/10/00

Phy1223 Fall 99

3

Course Introduction (cont.) • Grading – 5% Reading Quizzes – 15% Homework, based on post-class submission (with individual numbers) – bonus of up to 50% of the post-class homework for submitting the pre-class homework – 15% Friday in-class quizzes – 10% team project – 20% midterm examination – 35% final examination • More details of grading (including letter-grade translations) are on the web page

Lecture 1, 1/10/00

Phy1223 Fall 99

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2

Course Introduction (cont.) • Help: – office hours of Profs Sage, Perry, Bhattacharya, Wood – other times by appt – TA’s to be announces (w/ office hours) – Physics Workshop, 318 Churchill (starting next week) • Lecture notes: – will be posted on the web page in PDF format. • Available about1 hour before lecture • linked to course home page • Adobe Acrobat reader can be downloaded (free) from link on lecture notes page

– Recommend not copying them down during lecture. Concentrate on what is being said, and write down supplemental information. Lecture 1, 1/10/00

Phy1223 Fall 99

5

Course Intorduction (cont.) • Concept Questions in Lecture: – pick up a set of flash cards at the beginning of each lecture – when a question is shown, you will have about 30 sec to think about it on your own. Choose an answer which you think it correct. – You will then have another 30 sec or so to discuss it with the people around you. You can change your answer if you are convinced to do so. – When prompted, hold up the card corresponding to the answer you chose – further discussion in the lecture will depend on the response – please turn in the cards at the end of the lecture

Lecture 1, 1/10/00

Phy1223 Fall 99

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3

Course Introduction (cont) • Introductory Physics Lab (IPL), PHY1551 – don’t confuse the Friday Problem Solving Sessions (probably lists as “lab” on your schedules) with the IPL labs – separate course from this one (separate grade, different instructors) – designed, however to coordinate with this course – problems, demonstrations, etc. related to the IPL labs will occur regularly in this course – “Do I have to take the lab?” • it depends on your major (“yes” for most, including engineering and computer science) • if you’ve already taken it and passed it, you don’t have to take it again

Lecture 1, 1/10/00

Phy1223 Fall 99

7

Course Introduction (cont.) • Topics Covered in this course – descriptions of motion (velocity, acceleration) – vectors, motion in 2-dimensions and 3-dimensions – Newton’s laws – friction – uniform circular motion – energy and momentum – ... • Basic principles of most common objects, mechanical devices, planets, stars, etc. • Skills needed – algebra – graphing – calculus (not much at first, but gradually more as we go on) Lecture 1, 1/10/00

Phy1223 Fall 99

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4

Units and Measurement • Covered in HW assignment 0 • Units are important: remember the Mars probe • Common mistake #1, multiplying by conversion factors when you should divide (or vice versa) – Method to avoid mistake: carefully cancel units. For example, the density of lead is 19 g/cm3. What is the mass in kg of 50cm3 of lead?

19g 1kg = 0.95kg (50cm ) cm 1000g 3

Lecture 1, 1/10/00

3

Phy1223 Fall 99

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Units and Measure (cont.) • Common mistake #2: forgetting to raise conversion factors to appropriate powers. – Example: 1 inch is 2.54 cm. What is the mass of 1 cubic inch of lead?

(

)

3

2.54cm 19g 1.0in 3= in cm 3 3 16.4cm 19g 3 = 311g 1.0in 3 in cm

(

Lecture 1, 1/10/00

3

)

Phy1223 Fall 99

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5

1-Dimensional Motion • Displacement ∆x = x2 − x1 = x final − xinitial – change in position: – has units of distance (meters, etc.) – can be positive or negative according to direction – distance is the magnitude of displacement

x2

x1

0m

5m

– in this example, the displacement from x1 to x2 is -3 m, while the distance between them is 3 m.

Lecture 1, 1/10/00

11

Phy1223 Fall 99

1-Dimensional Motion • The ubiquitous x vs. t graph:

5 x (m)

∆x 0

Lecture 1, 1/10/00

5

Phy1223 Fall 99

10

t (s)

12

6

1-Dimensional Motion • Average velocity = displacement / elapsed time

5 x (m)

∆x 0

v=

5 [ W

=

10

t (s)

− 3.0m = −0.30m/s 10s

• also equal to the slope of the straight line connecting the intial and final points on the x vs. t graph. Lecture 1, 1/10/00

Phy1223 Fall 99

13

7

Phy1223 Fall 99

1

Course Introduction (cont.) • Sequence for a typical week – Monday: finish assigned reading and take reading quiz on Webassign (by 9:15 AM) – Monday: first lecture on the week’s topic – (Tuesday: post-class assignment from pervious week due at 4:00 PM) – Wed: second (last) lecture on the week’s topic – Wed-Fri: attempt assigned common problems on Webassign (before Friday class) – Friday: work with others on common problems in Problem Solving Session, take in-class quiz – Friday-Tues: Do individual problems Webassign (same as common problems but with different numbers) before Tues 4:00 PM Lecture 1, 1/10/00

Phy1223 Fall 99

2

1

Course Introduction (cont.) • The week visually Mon

( Tue

Wed

Webassign deadlines) Thu

Fri

Mon

Tues

Reading Quiz Lecutures Pre-Class hw PSS (w/ Quiz) Post-Class hw

Red: current week’s material, Green:previous, Blue: next Lecture 1, 1/10/00

Phy1223 Fall 99

3

Course Introduction (cont.) • Grading – 5% Reading Quizzes – 15% Homework, based on post-class submission (with individual numbers) – bonus of up to 50% of the post-class homework for submitting the pre-class homework – 15% Friday in-class quizzes – 10% team project – 20% midterm examination – 35% final examination • More details of grading (including letter-grade translations) are on the web page

Lecture 1, 1/10/00

Phy1223 Fall 99

4

2

Course Introduction (cont.) • Help: – office hours of Profs Sage, Perry, Bhattacharya, Wood – other times by appt – TA’s to be announces (w/ office hours) – Physics Workshop, 318 Churchill (starting next week) • Lecture notes: – will be posted on the web page in PDF format. • Available about1 hour before lecture • linked to course home page • Adobe Acrobat reader can be downloaded (free) from link on lecture notes page

– Recommend not copying them down during lecture. Concentrate on what is being said, and write down supplemental information. Lecture 1, 1/10/00

Phy1223 Fall 99

5

Course Intorduction (cont.) • Concept Questions in Lecture: – pick up a set of flash cards at the beginning of each lecture – when a question is shown, you will have about 30 sec to think about it on your own. Choose an answer which you think it correct. – You will then have another 30 sec or so to discuss it with the people around you. You can change your answer if you are convinced to do so. – When prompted, hold up the card corresponding to the answer you chose – further discussion in the lecture will depend on the response – please turn in the cards at the end of the lecture

Lecture 1, 1/10/00

Phy1223 Fall 99

6

3

Course Introduction (cont) • Introductory Physics Lab (IPL), PHY1551 – don’t confuse the Friday Problem Solving Sessions (probably lists as “lab” on your schedules) with the IPL labs – separate course from this one (separate grade, different instructors) – designed, however to coordinate with this course – problems, demonstrations, etc. related to the IPL labs will occur regularly in this course – “Do I have to take the lab?” • it depends on your major (“yes” for most, including engineering and computer science) • if you’ve already taken it and passed it, you don’t have to take it again

Lecture 1, 1/10/00

Phy1223 Fall 99

7

Course Introduction (cont.) • Topics Covered in this course – descriptions of motion (velocity, acceleration) – vectors, motion in 2-dimensions and 3-dimensions – Newton’s laws – friction – uniform circular motion – energy and momentum – ... • Basic principles of most common objects, mechanical devices, planets, stars, etc. • Skills needed – algebra – graphing – calculus (not much at first, but gradually more as we go on) Lecture 1, 1/10/00

Phy1223 Fall 99

8

4

Units and Measurement • Covered in HW assignment 0 • Units are important: remember the Mars probe • Common mistake #1, multiplying by conversion factors when you should divide (or vice versa) – Method to avoid mistake: carefully cancel units. For example, the density of lead is 19 g/cm3. What is the mass in kg of 50cm3 of lead?

19g 1kg = 0.95kg (50cm ) cm 1000g 3

Lecture 1, 1/10/00

3

Phy1223 Fall 99

9

Units and Measure (cont.) • Common mistake #2: forgetting to raise conversion factors to appropriate powers. – Example: 1 inch is 2.54 cm. What is the mass of 1 cubic inch of lead?

(

)

3

2.54cm 19g 1.0in 3= in cm 3 3 16.4cm 19g 3 = 311g 1.0in 3 in cm

(

Lecture 1, 1/10/00

3

)

Phy1223 Fall 99

10

5

1-Dimensional Motion • Displacement ∆x = x2 − x1 = x final − xinitial – change in position: – has units of distance (meters, etc.) – can be positive or negative according to direction – distance is the magnitude of displacement

x2

x1

0m

5m

– in this example, the displacement from x1 to x2 is -3 m, while the distance between them is 3 m.

Lecture 1, 1/10/00

11

Phy1223 Fall 99

1-Dimensional Motion • The ubiquitous x vs. t graph:

5 x (m)

∆x 0

Lecture 1, 1/10/00

5

Phy1223 Fall 99

10

t (s)

12

6

1-Dimensional Motion • Average velocity = displacement / elapsed time

5 x (m)

∆x 0

v=

5 [ W

=

10

t (s)

− 3.0m = −0.30m/s 10s

• also equal to the slope of the straight line connecting the intial and final points on the x vs. t graph. Lecture 1, 1/10/00

Phy1223 Fall 99

13

7