7 September

Administrative Chores

• Pass out Syllabus
• Comments on contact methods, office hours, web page, textbook, lectures, quizzes, homework.
• Grading policy, grading scale, labs.
• Exams: Note the exam dates. If you have a conflict with an exam date, you must talk with me in advance to request an excused absence and a make-up exam date! The exam problems will be based on the assigned homework problems.
• Course outline -- complete version on Thursday.
• Calculators.
• Study:
  • Establish and keep to a regular study schedule.
  • Read the assigned sections before lecture.
  • Attempt the assigned problems before quiz section.
  • Bring questions to lecture, quiz sections, or office hours.
  • It can be helpful to work problems with friends -- but avoid the temptation of letting your friends do all the work for you.
  • Physics is like sports: if you want to be good at it you must practice.

Chapter 1

What Is Physics?

From Webster's Dictionary:

From Greek, physikos, meaning of nature,

1 : a science that deals with matter and energy and their interactions
2 a : the physical processes and phenomena of a particular system b : the physical properties and
composition of something

We will be most concerned with (1). So, physics is the science that deals with matter and energy and their interactions. What isn't covered by this definition? Nearly everything around us is either matter or energy, so this definition is rather broad. In this course we will be concerned with the topics of mechanics, thermodynamics, and optics. We begin with mechanics.

Dimensions: Length, Mass, and Time

Mechanics deals with the motion of objects. To describe the motion of something, we need to know where it is at some instant in time, i.e. we need to know distances (length) and times. Additionally, when looking at what causes or controls motion, we will need to refer to the mass of objects -- the same cause of motion will have different effects on objects of different mass.

As a convenience, we will use international standards for length, mass, and time: the meter, second, and kilogram.

Definitions for length, mass and time are given in the text.

Tables showing the range of values for masses, lengths, and times. Notice that these quantities can have enormous variations from small to large.

Prefixes for Metric Units

See table in the text.

Building Blocks of Matter

Matter is composed of molecules which are made of atoms. Atoms are composed of a positive nucleus surrounded by a cloude of negatively charged electrons. The nucleus is composed of protons and neutrons which are in turn composed of quarks. And it is now hypothesized that electrons and quarks are actually small vibrating strings that exist in an 11 dimensional universe!

Dimensional Analysis or "You Can't Add Apples and Oranges"

We can treat the dimensions of quantities almost like variables. A length (L) divided by another length (L/L), is unit-less, since the two lengths cancel. Length divided by length squared (L/L²) is one over length. The example from the text demonstrates an application, where, without knowing what acceleration is, we can check that at least the dimensions work out properly.