PHYSICS 231 INTRODUCTORY PHYSICS I www.pa.msu.edu/courses/phy231

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PHYSICS 231INTRODUCTORY PHYSICS
Iwww.pa.msu.edu/courses/phy231

• Scott Pratt
• prattsc_at_msu.edu
• [phone], ext. 2016
• Office Hours T-R, immediately after class in
  4208A BPSTuesday 100-230 PM in 1248 BPS

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Strosacker Center, 1248 BPS Bldg.
Homework

• Graded electronically with LON-CAPA http//msu.lo
  ncapa.org
• Due Wednesdays at 1000 AM
• No HW due week after Exam 1 and Exam 3

• Monday 900 AM - noon, 1230-600 PM
• Tuesday 830 AM - 600 PM
• Wednesday 830 AM - 1000 AM

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EXAMS

• 4 Midterms (on Thursdays during class time)
• 1 Final
• 11 questions one each midterm, graded on scale of
  10
• Drop lowest of 4 midterms, no make-ups
• 22 questions on final, graded on scale of 20
• Exams are closed book - closed note
• Midterms will have HIGH overlap with homework
• Midterms 2, 3 and 4 will include problem from
  previous midterm
• Final will be made of reworded Midterm problems

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GRADES
4 Midterms 60 Feb. 5, Mar. 4, Apr. 1, Apr. 29 During class in 1410 BPS (right here) Lowest score dropped No makeups 11 questions, graded on scale of 10 Questions largely from homework
Final Exam 30 May 4, 545-745 PM, location TBA 22 questions, graded on scale of 20 Reworded Midterm problems
Homework 10 LON-CAPA, www.loncapa.org Log-in with pilot ID password
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Textbook

• Serway and Faughn
• Old editions are fine

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Succeeding in Physics 231

• Do your homework!
• Use the help room (1248 BPS) ! Stay away from
  ALLMSU
• Make sure you understand both why and why not
• Interrupt the lecturer

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General Physics

• First Semester (Phy 231)
• Mechanics
• Thermodynamics
• Simple harmonic motion
• Waves

• Second Semester (Phy 232)
• Electromagnetism
• Relativity
• Modern Physics
• (Quantum Mechanics, , etc.)

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Mechanics

• Half the course
• Quantified largely by Galileo
• Problems involvevelocity, acceleration, mass,
  momentum, energy, torque, angular momentum,
  moment of inertia

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UNITS (Systéme Internationale)
Dimension SI (mks) Unit Definition
Length meters (m) Distance traveled by light in 1/(299,792,458) s
Mass kilogram (kg) Mass of a specific platinum-iridium allow cylinder kept by Intl. Bureau of Weights and Measures at Sèvres, France
Time seconds (s) 9,192,631,700 oscillations of cesium atom
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Standard Kilogram at Sèvres
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Dimensional Analysis
Dimensions units can be treated algebraically.
Variable from Eq. x m t v(xf-xi)/t a(vf-vi)/t
dimension L M T L/T L/T2
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Dimensional Analysis
Checking equations with dimensional analysis
(L/T2)T2L
L
(L/T)TL

• Each term must have same dimension
• Two variables can not be added if dimensions are
  different
• Multiplying variables is always fine
• Numbers (e.g. 1/2 or p) are dimensionless

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Example 1.1
Check the equation for dimensional consistency
Here, m is a mass, g is an acceleration,c is a
velocity, h is a length
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Example 1.2
Consider the equation
Where m and M are masses, r is a radius andv is
a velocity. What are the dimensions of G ?
L3/(MT2)
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Units vs. Dimensions

• Dimensions L, T, M, L/T
• Units m, mm, cm, kg, g, mg, s, hr, years
• When equation is all algebra check dimensions
• When numbers are inserted check units
• Units obey same rules as dimensionsNever add
  terms with different units
• Angles are dimensionless but have units (degrees
  or radians)
• In physics sin(Y) or cos(Y) never occur unless Y
  is dimensionless

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Example 1.3
Grandma traveled 27 minutes at 44 m/s. How many
miles did Grandma travel?
44.3 miles
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Prefixes
In addition to mks units, standard prefixes can
be used, e.g., cm, mm, mm, nm