PH 202L Physics 2 Supplementary Informaion University Of South Alabama

University of South Alabama

PH 202L Physics 2 Supplementary Informaion University Of South Alabama

1. First we need to review the basic physics concepts of FORCE:
Force: an interaction between two objects results in a force acting on each of the two objects.
Unit of force: [F] = 1 N (Newton)
Forces are vectors and, like any other vectors, are represented by arrows. Vectors can be added
using the familiar head-to-tail method.
In general, all forces can be placed in two categories:
Contact Forces – the objects interacting are in physical contact with each other. Examples of
contact forces include frictional forces, tensional forces, normal forces, air resistance forces, and
applied forces.
Action at a Distance forces – these are known as fundamental forces. In this case the interaction
occurs through a force field rather than by “physical contact.” There are four conventionally accepted
fundamental interactions:
1. gravitational (https://en.wikipedia.org/wiki/Gravity) ,
2. electromagnetic (https://en.wikipedia.org/wiki/Electromagnetism) ,
3. strong nuclear (https://en.wikipedia.org/wiki/Strong_interaction) , and
4. weak nuclear (https://en.wikipedia.org/wiki/Weak_interaction) .
The gravitational force was studied in Mechanics, the first part of the College Physics book.
In this course we will discuss the electromagnetic force and we will begin by studying the electrostatic
force in this module.
2. ELECTRIC CHARGE (Q) is a Fundamental Quantity
SI unit: [Q] = 1 C (Coulomb)
Properties of Electric Charges:
Two types of charges exist: they are called positive and negative
Like charges repel and unlike charges attract
Nature’s basic carrier of positive charge is the proton.
Nature’s basic carrier of negative charge is the electron
Electric charge is always conserved
Charge is not created, only exchanged
Objects become charged because negative charge is transferred from one object to another.

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