Transcript Science is a systematized body of knowledge based on

Science is a systematized
body of knowledge based
on facts. It is a study of
life and non-life. It is a
never-ending quest and
the greatest creation of
God.
Science
Natural Science
Physical Science
Social Science
Applied Science
Biological Science
Physics, Chemistry, Meteorology,
Astronomy, Geology, Oceanography
Physics is the scientific study of
matter and energy. It deals
with the fundamental
concepts like time,
motion, forces, space,
matter, energy, gravity,
and radiation.
I. Measurement is the
process of comparing an
unknown quantity with a
known or fixed quantity
called standard.
Fundamental
Quantities ~
measurement chosen
arbitrarily and
independently of the
scales of other
quantities.
7 Fundamental Units
meter (m) – distance
kilogram (kg) – mass
second (s) – time
ampere (A) – electric current
Kelvin (K) – temperature
mole (mol) – amount of substance
candela (cd) – intensity of light
Derived Quantities ~
obtained by
multiplying or
dividing the
fundamental units
System of Units
1. English System of Units ~
developed by the Englishspeaking countries of the world.
Common units:
Inch, foot, yard, mile, rod (16 ½ ),
furlong(660 ft)
2. Metric System~ proposed in
1971 by the French National
Assembly
Common Units:
Meter (length), gram (mass), liter
(volume)
3. International System of
Units (SI) ~ established
by the Treaty of the Meter
(1875)
Prefixes
mega
kilo
hecto
deka
deci
centi
milli
micro
nano
Pico
Symbol
M
k
h
da
d
c
m
μ
n
p
Equivalent
106
103
102
10
10-1
10-2
10-3
10-6
10-9
10-12
Length
Defined as the interval or distance
between two points
“How long?”, “How far?”, “How
high?”
Mass
The amount of matter in an
object
Weight
The measure of force exerted by
Earth on an object
Time
The interval between two events at the
same place in space.
Temperature
The measure of the average kinetic
energy in molecules or atoms of
substance.
Conversion of
Units/Dimensional Analysis
*The key to using dimensional
analysis is the correct use of
conversion factors to change one
unit into another. A conversion
factor is a fraction whose
numerator and denominator are the
same quantity expressed in
different units.
e.g.
2.54 cm and 1 in are the same length, 2.54
cm=1 in. This relationship allows us to
write two conversion factors:
2.54 cm
1in
and
1 in
2.54 cm
Thus the length in cm of an object that is
8.50 in long is given by:
Desired
Unit
Number of cm= (8.50 in) 2.54 cm = 21.6 cm
1in
Given
Unit
To multiply a quantity by a conversion factor,
the units multiply and divide as follows:
Given unit X desired unit = desired unit
given unit
If a woman has a mass of 115 lb,
what is her mass in grams?
1 lb= 453.6 g
Mass in grams = 115lb (453.5)=5.22 x 104
(1 lb)
g
10 m = ____________ km
2km = ____________ cm
250 mL = ___________ L
1500 cc = ___________ L
Significant Figures
1. Any digit that is not zero is significant.
e.g.
226.28 - __________
14344.21 – ________
2. Zeros between non-zeros are significant.
e.g.
1002.5 - _________
3. Zeros to the left of the first non-zero digit
are not significant.
e.g.
000 226 – _______
0.002 8 - ________
4. If the number is equal to or greater than
one (1), then all zeros to the right of the
decimal point are significant.
e.g.
457.10 - _________
400.00 - _________
5. If the number is less than one, then
only zeros that are at the end of the
number and between non-zero digits
are significant.
e.g. 0.01020 - ________
0.060 ________
6. For the numbers that do not contain
decimal points, the trailing zeros
may or may not be significant.
e.g. 3 000 000 - __________
3 000 000 - __________
Operations on Significant Figures
1. Addition and Subtraction
The number of significant
figures to the right of the
decimal point in the final sum or
difference is determined by the
lowest number of significant
figures to the right of the
decimal point in any of the
original numbers.
2. Multiplication and Division
The number of significant
figures in the final product or
quotient is determined by the
original number that has the
smallest number of significant
figures.
Accuracy
and
Precision
Accuracy is how close a measurement is
to the actual(accepted) value.
Example: Your watch
is accurate if it is
close to the time
kept by the National
Institute of Standards
and Technology
(N.I.S.T.)
Precision is how
close a set of
measurements are
to each other.
Example: A field
goal kicker is
precise if he kicks
the ball through the
goal posts every
time.
Scientific Notation
- also sometimes known as
exponential notation, is a way
of writing numbers that
accommodates values too large
or small to be conveniently
written in standard decimal
notation.
General Form:
M x 10n
where
N = is a number equal to or greater than 1 but
less than 10
n = is a positive or a negative integer
Express the following into scientific notation of
3 SF:
1. 145 000 =
2. 9 562 157 =
3. 0.000 075 =
Operations on Scientific Notation
MULTIPLICATION of exponentially notated
numbers.
General format:
(Nx10x) (Mx10y) = (N)(M) x 10x+y
e.g. (3 x 104) (1 x 102) =
DIVISION of exponentially notated numbers.
General format:
(N x 10x) / (M x 10y) = N/M x 10x-y
e.g. (6 x 105)/(2 x 102) = ________
ADDITION and SUBTRACTION
General format:
(N x 10x) + (M x 10x) = (N+M) x 10x
(N x 10x) - (M x 10x) = (N-M) x 10x
e.g. (2.3 x 10-2) + (3.1 x 10-3) = ________
(2.3 x 10-2) - (3.1 x 10-3) = ________
II. Motion and Force
Mechanics~ the scientific study of
motion
Motion~ a change in position with
respect to a reference point/frame of
reference
Mechanics
Kinematics
Description of
how objects move
Dynamics
Relation of motion
to its cause
which is force
Kinematics
Distance and Displacement
Distance (d) ~ linear dimension between
two points measured along the actual
path
Displacement (d)~ a straight line distance
from the starting to the end point and
expressed with direction
Speed and Velocity
Speed~ the ratio of the distance
traveled with respect to time.
v=d/t
Where
v is speed
d is distance
t is time
Velocity is the actual speed stated
with direction.
a. A ball rolling at 5m/s forward
b. A car traveling at 60 km/h east
c. Typhoon Frank moving at 15
km/h west northwest
V=d/t
Where
v is velocity
d is displacement
t is time
1. A ball is rolling on the floor. It covers 15
m in 10.0 s. what is its speed as it
moves?
2. A kangaroo is hopping at a speed of 15
m/s. How far would it be in 3.0 s?
3. What is the velocity of a police car that
moves 450 m E in 25 seconds?
Acceleration is the rate of change of velocity.
An object may accelerate if;
a. It increases or decreases its as it moves
along the same direction,
b. It changes its direction as it moves with the
same speed, or
c. It changes both its speed and direction.
a= vf - vi
t
Where
a is acceleration
vf is final velocity
vi is initial velocity, and
t is time
1. A ball is initially at rest on top of an
inclined plane. It rolls downward and hits
the bottom of the inclined plane after 3.0
s with a speed of 1.5 m/s. What is the
acceleration of the ball as it rolls?
2. A car is initially moving at 5.0 m/s. it is
accelerating uniformly by 2.0 m/s2. how
fast will it be moving after 10.0 s?
Dynamics
Force is commonly known as any kind of
push or pull on an object.
Newton’s Laws of Motion
Law of Inertia:
An object at rest remains at
rest and an object in motion
will remain in motion at a
constant velocity unless an
unbalanced force acts on it.
Law of Acceleration:
Force equals mass X acceleration
When a net force acts on an
object with mass m, the object
accelerates with the acceleration
given by
F=ma
Law of Interaction:
For every action, there is an
equal and opposite reaction.
“Every force must have an equal
and opposite force”
Uniform Circular Motion
A body moving at constant speed in
circular path is accelerating because
the direction of its velocity is
constantly changing. The direction of
this acceleration is toward the center
of the path and its magnitude is given
by
a = v2
R
Friction
In general when two objects are
in contact there are two possible
forces acting between them. The
force perpendicular to the
surface of contact we call the
normal force and the force
parallel to the surface of contact
is called friction.
Laws of Planetary Motion
1. Each planet moves in an elliptical
orbit, with the Sun at one focus of
the ellipse.
2. A line from the Sun to a given point
sweeps out areas in equal times.
3. The periods of the planets are
proportional to the 3/2 powers of
the major axis lengths of their
orbits.
Law of Universal Gravitation
Newton’s Law of Gravitation states that two
particles with masses m1 and m2, a
distance r apart, attract each other with
forces of magnitude
Fg = G m1m2
r2
Four Fundamental Forces
1. Strong Nuclear force is the strongest
and the reason for the binding of
protons and neutrons to form a
nucleus.
2. Electromagnetic force is responsible
for binding electrons to nucleus
forming atoms as a result.
3. Weak nuclear force governs
radioactive decay of atomic nuclei.
4. Gravitational force is the weakest
but its effect is felt on a large scale.
Fundamental
Force
Relative
strength
Action distance
Strong nuclear
1
Short range
(10-15 m)
Electromagnetic 10-3
Infinite
Weak nuclear
10-8
Extremely short
range (10-17 m)
Gravitational
10-45
Infinite
III. Work, Energy and Power
Work is what is accomplished when force
moves through a distance.
Specifically, work done on an object is
defined as the product of the magnitude of
the displacement and the component of
the force parallel to its displacement.
W= Fd
3 conditions that had to be
considered in order to say that
work is done:
1. There must be a force applied.
2. There must be a displacement.
3. There must be component of the
force along the direction of
displacement.
Is there a work done?
1. A boy lifts a chair upward.
2. A boy pushes a table forward and
the table moves.
3. A mother pushes a grocery cart at
30° with respect to the ground.
4. A person pushing against the wall,
the wall remains stationary.
5. A porter carrying a sack of rice on
his shoulder walks 50 m forward.
Practice exercises:
1. Coming from school, Elmer pushes the
door of their house by a force of 50N.
The door moves forward by 0.5 m. How
much work did Elmer do?
2. John lifts a 10.0 N box to a height of 5 m
from the ground. In the same way, Jean
lifts 8.0 N box to a height of 2.6 m. Who
does more work?
Power
The rate at which work is done.
In equation form,
P=W/t
The SI unit of power is watt (W).
Sample problem:
1. A firefighter weighs 700 N. He climbs a
flight of stairs 7.0 m high in 17 s. How
much work did the firefighter
accomplished? What is his power rating in
doing the work?
Different Forms of Energy
1. Potential Energy- stored energy
a. Chemical potential energy
b. Electrical potential energy
c. Elastic potential energy
d. Magnetic potential energy
e. Gravitational potential energy
Gravitational potential energy
GPE = mass x acceleration due to gravity x
height
GPE = m x g x h
2. Kinetic Energy
Energy carried by objects in
motion.
KE = ½ mv2
3. Thermal Energy
The total kinetic and potential
energy of the molecules of an
object.
4. Chemical Energy
5. Mechanical Energy
6. Light Energy
7. Electrical Energy
8. Sound Energy
Law of Conservation of
Energy
Energy is conserved; can
neither be created nor
destroyed. It can only be
transformed from one form
to another.