• Scientists use number to describe
measurements. Such a number is called a
physical quantity.
• is a quantity which can be
measured and can be
expressed as the
combination of a numerical
value and a unit
• Examples: mass, length,
temperature, velocity,
speed, force, work, energy
• Internationally known by
the abbreviation SI UNITS
(for Systeme International),
is the modern form of the
metric system and the
world’s most widely used
system of measurement.
time
t
second
s
length
l, x, r, etc.
meter
m
mass
m
kilogram
kg
electric current
I, i
Ampere
A
thermodynamic
temperature
T
Kelvin
K
amount of substance
n
mole
mol
luminous intensity
lv
candela
cd
Time is the progression
of events from the
past to the future
power derived from
the utilization of
physical or chemical
resources
the amount of matter
present in any object
or body
the degree or intensity
of heat present in a
substance or object
the amount of space
that a substance or
object occupies
continuous physical
force exerted on or
against an object by
something in contact
with it
Length is how long
something is, like the
length of a snake from
it’s mouth to the tip of
it’s tail. Width is how
broad something is,
like how wide a river is.
1.If 1 pound = 16 ounces, how many pounds are
in 435 ounces?
2.A student averaged 45 miles per hour on a trip.
What was the student’s speed in feet per
second?
3.A child is prescribed a dosage of 12 mg of a
certain drug per day and is allowed to refill his
prescription twice. If there are 60 tablets in a
prescription, and each tablet has 4 mg, how
many doses are in the 3 prescriptions?
Scientific notation is a form of
presenting very large numbers or
very small numbers in a simpler
form. A number is written in
scientific notation when a number
between 1 and 10 is multiplied by a
power of 10. For example,
650,000,000 can be written in
scientific notation as 6.5 ✕ 10^8.
1.Write the number 34100000 in
scientific notation.
2.Write the number 0.00041 in scientific
notation.
3.Convert 2.89 × 10-6 to standard form.
are used to establish the
number which is presented in
the form of digits. These digits
carry a meaningful
representation of numbers.
All nonzero digits
are significant.
-For example, the
value 211.8 has four
significant figures.
All zeros that are found
between nonzero digits
are significant.
-Thus, the number
20,007, with three 0s
between the 2 and 7, has
a total of five significant
figures.
Leading zeros (to the left of
the first nonzero digit) are
not significant.
-A value such as 0.0085, for
example, has two significant
figures because the 0s
before the 8 are
placeholders and are not
significant.
Trailing zeros for a whole
number that ends with a
decimal point are significant.
-For example, a value written as
320. shows the decimal point,
which indicates that the 0 to
the right of the 2 was measured;
therefore, the value has a total
of three significant figures.
Trailing zeros to the
right of the decimal
place are significant.
-This means a value such
as 12.000 has a total of
five significant figures
For any value written in
scientific notation as A
×10x, the number of
significant figures is
determined by applying the
above rules only to the
value of A
-Example 4.5 × 103 has two
significant figures
1.36.7 m
2.0.006606 s
3.2,002 kg
4.306,490,000 people
5.0.42000
The answer carries the same
number of decimal places as
the number with the fewest
decimal places.
The answer should have the
same number of significant
figures as the factor with the
fewest significant figures.
1. 34.683 + 58.930 +
68.35112
2.45001 - 56.355 - 78.44
3.98.1 x 0.03
4.6.90 / 2.8952
1.Imagine that you are driving your car in Canada. As you're driving
along, you notice that the speed limit signs have numbers like 120
(on the highway) and 50 (in the city). As you start to speed up, you
realize that the signs are in km/hour. Unfortunately, your
speedometer only reads in mi/hour. Figure out how fast you're
allowed to go if the sign says: A. 120 km/hr; B. 75 km/hr; C. 50km/hr
2.Write the number 568,200,000,000 in scientific notation.
3.Convert 1.36 × 10^7 from scientific notation to standard notation.
4.How many significant figures in each term: A. 34.6209; B. 0.003048;
C. 4032.090
5. 0.003 + 3.5198 + 0.0118
6.36.01 - 0.4 - 15
7.8.578 / 4.33821
8.57 x 7.368