PHYSICS 231 INTRODUCTORY PHYSICS I Scott Pratt (517) , ext Office Hours: T-R, immediately after class in 4208A BPS Tuesday: 1:00-2:30 PM in 1248 BPS

Strosacker Center, 1248 BPS Bldg. Monday 9:00 AM - noon, 12:30-6:00 PM Tuesday 8:30 AM - 6:00 PM Wednesday 8:30 AM - 10:00 AM Graded electronically with LON-CAPA Due Wednesdays at 10:00 AM No HW due week after Exam 1 and Exam 3 Homework

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

GRADES 4 Midterms60%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 Exam30%May 4, 5:45-7:45 PM, location TBA 22 questions, graded on scale of 20 Reworded Midterm problems Homework10%LON-CAPA, Log-in with pilot ID & password

Textbook Serway and Faughn Old editions are fine

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

General Physics First Semester (Phy 231) Mechanics Thermodynamics Simple harmonic motion Waves Second Semester (Phy 232) Electromagnetism Relativity Modern Physics (Quantum Mechanics, …, etc.)

Mechanics Half the course Quantified largely by Galileo Problems involve: velocity, acceleration, mass, momentum, energy, torque, angular momentum, moment of inertia…

UNITS (Systéme Internationale) DimensionSI (mks) UnitDefinition Lengthmeters (m)Distance traveled by light in 1/(299,792,458) s Masskilogram (kg)Mass of a specific platinum- iridium allow cylinder kept by Intl. Bureau of Weights and Measures at Sèvres, France Timeseconds (s)9,192,631,700 oscillations of cesium atom

Standard Kilogram at Sèvres

Dimensional Analysis Dimensions & units can be treated algebraically. Variable from Eq.xmtv=(x f -x i )/ta=(v f -v i )/t dimensionLMTL/TL/T 2

Dimensional Analysis Checking equations with dimensional analysis: L (L/T)T=L (L/T 2 )T 2 =L 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  ) are dimensionless

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

Example 1.2 L 3 /(MT 2 ) Consider the equation: Where m and M are masses, r is a radius and v is a velocity. What are the dimensions of G ?

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 dimensions: Never 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

Example 1.3 Grandma traveled 27 minutes at 44 m/s. How many miles did Grandma travel? 44.3 miles

Prefixes In addition to mks units, standard prefixes can be used, e.g., cm, mm,  m, nm