Content:
I. Introduction
II. Measurements
III. Work, Energy and Power
IV. Waves
V. Sound
VI. Light
VII. Lens
VIII. Light Source
IX. Theory of Relativity
Physics
Physics is a branch of science which deals with the study
of matter, energy, force, and motion and the way they
relate to each other.
MEASUREMENT
Precision: is a measure of the consistency or
repeatability of measurements.
Accuracy: is the degree of exactness of a measurement
compared to the expected value, or most probable value of
the variable being measured.
Two system of measurements:
1. English System
Used only in the United States and some
African countries
The system of unit used is the FPS of the
“foot-pound-second”
2. Metric System
In 1950, it has been known officially as the
“International System” or SI (the
abbreviation for its French name, Systeme
Internationale).
Two system of units are known: the MKS
(meter-kilogram-second) and the CGS
(centimeter-gram-second)
7 fundamentals SI Units
Quantity Unit Name Symbol
Length Meter m
Mass Kilogram kg
Time Second s
Electrical current Ampere a
Temperature Kelvin k
Amount of substance Mole mol
Luminous intensity Candela cd
Note: SI derived units are constructed from the combination of
the fundamental units. Example: The SI unit of force is Newton
(N) which is kg-m/s^2
Work, Energy and Power
Work: is defined as the product of the force and
displacement in the direction of the force
W=Fdcosθ ;W =Fd (if θ=0°)
Where:
F – force
D – displacement
θ
– angle between the force and displacement
Energy: is the capability to do work
a. Potential Energy : is the energy possessed by an
object by virtue of its position or configuration
P . E =wh=mgH ; g=9.81 m/s2
b. Kinetic Energy : is the energy possessed by an
object by virtue of its motion.
K . E=1
2m v2
Power: is the time rate of doing work
P=W
t=Fd
t=Fv
Unit conversions for power:
1 --- GEAS GENERAL PHYSICS: Prepared by: EJBR
