Transcript Outline

May
st
21
2007
Fundamentals of Physics I
PHYS 1501
Course Code 2501
SUMMER 2007
09:00 am – 12:00 noon
Physics 1501: FUNDAMENTALS OF PHYSICS I
Course Code 2501
• Dr. Tom N. Oder
• WBSH 1016, E-mail: [email protected], phone
(330) 941-7111
• Website: http://www.ysu.edu/physics/tnoder
• Office Hours: M, W, F 12:00 noon – 1:00 pm.
• Research: (Wide Band Gap) Semiconductors.
Link to Class web page:
http://www.ysu.edu/physics/tnoder/X07-PHYS2501/index.html
Required Materials
(a) Text: College Physics, By A. Giambattista
et al., 2nd Edition
(b) CPS-RF response pad.
(c) Sign up online at www.eInstruction.com.
A strong background in algebra (Math 1504 or
High school algebra and trigonometry)
Hard Cover version
YSU Customized version
Vol. 1
CPS RF Clickers
Location of Serial Number
Regular/Punctual Class attendance encouraged.
Homework: In the Syllabus, will not be graded.
For your practice
Quizzes:
• Short in-class + Worksheets. No make-ups.
• Least three scores will be dropped.
Exams
No make-ups will be given.
Midterm1: Ch.1, 2, 3, 4 on Fri. June 1st.
Midterm2: Ch. 5, 6, 7 on Mon. June 11th.
Midterm3: Ch.8, 10, 11 on Fri. June 22nd.
Finals: Ch. 1-8, 10-12 on Fri. June 29th
Exam questions will be developed from questions
in the Homework/Quizzes/Worksheets/Class notes.
Grading:
Quizzes/Worksheets :100 points
Midterms (100 points each): 300 points
Final Exams: 200 points.
Final Grade:
540 – 600 points (90% - 100%) = A
480 – 539 points (80% - 89%) = B
420 – 479 points (70% - 79%) = C
360 – 419 points (60% - 69%) = D
0 – 359 points (0% - 59%) = F
No bonus points, no grade-curving
Cell Phones:
• Cell phones must be turned off
during class and exam sessions.
•A student whose cell phone audibly
goes on during any exam will lose
5% of his/her points in that exam.
Chapter 1: INTRODUCTION
• Physics: branch of physical science that
deals with energy, matter, space and time.
• We will use certain words common in
everyday speech, but their scientific
definition may be completely different
from their everyday common meanings.
Eg. Velocity, speed, acceleration, work
etc.
§ 1.3: Factor, Proportion:
• Factor (or ratio) – number by which a
quantity is multiplied or divided when
changed from one value to another.
• Eg. The volume of a cylinder of radius r and
height h is V = r2h. If r is tripled, by what
factor will V change?
• Vold = r2h, Vnew = (3r)2h = 9. r2h, Vnew/Vold
= 9. V will increase by a factor of 9.
Proportion
• If two quantities change by the
same factor, they are directly
proportional to each other.
• A  B – means if A is doubled, B
will also double.
• S  r2 – means if S is decreased by
factor 1/3, r2 (not r!) will also
decrease by the same factor.
Inverse Proportion
• If A is inversely proportional to B –
means if A is increased by a certain
factor, B will also decrease by the
same factor.
• K inversely proportional to r [K 1/r]
– means if r is increased by factor 3, K
will decrease by the same factor.
§ 1.4: Scientific notation:
• Rewriting a number as a product of a number
between 1 and 10 and a whole number power
of ten.
• Helps eliminate using too many zeros.
• Helps to correctly locate the decimal place
when reporting a quantity.
• Eg: Radius of earth = 6,380,000 m
= 6.38 x 106 m
Radius of a hydrogen atom
= 0.000 000 000 053 m = 5.3 x 10-11 m.
Precision in Scientific Measurements
• In reporting a scientific
measurement, it is important to
indicate the degree of precision in
the number. This helps other people
to appreciate the accuracy of your
measurement.
• This can be done using absolute (or
percentage) error, significant figures
and order of magnitude.
(a)Absolute/Percentage error:
Eg. Length of a notebook = 27.9 ± 0.2 cm
 Actual length is somewhere between 27.9
– 0.2 and 27.9+0.2, ie 27.7 and 28.1 cm
 ± 0.2 is the estimated uncertainty.
 0.2 is the absolute uncertainty.
 27.9 is the central value
 27.7 and 28.1 are called extreme values.
Percentage Uncertainty
Absolute Value
x100
Percentage uncertainty =
Central Value
Eg. Length of a notebook = 27.9 ± 0.2 cm
% Uncertainty = 0.2
x 100  0.7%
27.9
(b) Significant Figures:
Number of reliably known digits in a
measurement. Includes one “doubtful” or
estimated digit written as last digit.
Eg. 2586
[6 is the last digit. It is the doubtful digit].
Eg. 25.68
[8 is the last digit. It is the doubtful digit].
Significant Figures contd:
• All nonzero digits are significant.
• Zeros in between significant figures are
significant.[2,508]
• Ending zeros written to the right of the decimal point
are significant. [0.047100].
• Zeros written immediately on either sides of decimal
point for identifying place value are not significant.
[0.0258, 0.258]
• Zeros written as final digits are ambiguous.[25800] To
remove ambiguity, rewrite using scientific notation.
• Eg. (i) 58.63 – 4 sf, (ii) 0.0623 – 3 sf, (iii) 5.690 x 105 – 4
sf. (iv) 25800 – 2.58x 104 = 3 sf, 2.580x 104 = 4 sf,
2.5800x 104 = 5 sf.
Significant Figures in Addition/Subtraction
The sum/difference can not be more precise
than the least precise quantities involved.
ie, the sum/difference can have only as many
decimal places as the quantity with the least
number of decimal places.
Eg: 1) 50.2861 m + 1832.5 m + 0.893 m =
2) 77.8 kg – 39.45 kg =
What is the difference between
accuracy and precision?
Significant Figures in Multiplication/Division
The product/quotient can have only as
many sf as the number with the least
amount of sf.
Eg: 1) What is the product of 50.2861 m
and 1832.5 m?
2) What is 568 m divided by 2.5 s?
(c) Order of Magnitude
– (roughly what power of ten?) To determine
the order of magnitude of a number:
• Write the number purely as a power of ten.
• Numbers < 5 are rounded to 100
• Numbers  5 are rounded to101
• Eg. 754 =7.54 x 102 ~101 x 102 = 103. The
order of magnitude of 754 is 3.
• 403,179 = 4.03179 x 105 ~100 x 105 = 105 =
5 O/M
• 0.00587 ~ orders of magnitude = - 2 (how?).
§ 1.5: Units
We will use the SI system of units
which is an international system of
units adapted in 1960 by the General
Council of Weights and Measures.
• In SI system:
Length is measured in meters (m).
Mass is measured in kilograms (kg).
Time is measured in seconds (s).
• Other fundamental quantities and
their units in the SI system includes
Temperature (in Kelvin, K),
Electric current (in Amperes, A)
Amount of substance (in mole, mol) and
Luminosity (in Candela, cd).
• The SI system is part of the metric
system which is based on the power of
ten.
Converting Between Units
Eg. Convert 65 miles/hour to SI units.
1 mile = 1.609 km = 1609 m.
1 hour = 3,600 seconds
65 miles 65 x 1609m

 29.1 m / s
1 hour
1 x 3600 s
§ 1.6: Dimensional Analysis
Dimensions – Units of basic (Fundamental)
quantities:
Mass [M], Length [L], Time [T]
We can only add, subtract or equate
quantities with the same dimensions.
Eg. 1 Check if the expression v = d2/t is correct,
where v = speed (in m/s), d is the distance (in
m) and t is time (in s).
Quantity Dimension
[M ]
V
[T ]
d2
T
[M]2
[T]
v = d2/t
[ M ] [ M ]2

[T ]
[T ]
Hence eqn is
not correct
Eg. 2: If the equation was now correctly written
as v = kd2/t, what must be the units of k?
[M ]
[ M ]2
1
k
k
[T ]
[T ]
[M ]
The units of k must be kg-1
§ 1.7-1.9: Reading Assignment