2. PHYSICS
•What are your impressions, notions about it?
•Branch of Science that deals with the study of…
•What do you think the notable contributions of
Physics to humanity?
3. PHYSICS
•Laws of Motion
•Light, Matter and Physical Processes
•Quantum Mechanics (towards inventions
leading to the components in a cell phone)
4. PHYSICS
•Physics is Fun. It is an exciting adventure in the quest to
find out patterns in nature and find means of
understanding phenomena through careful deductions
based on experimental verification.
•Physics requires discipline: Effort to Learn, Find yourTime
to Study (advance readings, research, and practice…)
•Physics is LIFE.
5.
6. Lesson 1: Physical
Quantities
•PHYSICS is an Experimental Science.
•PHYSICISTS perform experiments to test
hypotheses.
•CONCLUSIONS in experiment are derived from
measurements.
8. •Since 1960 the system of units used by
scientists and engineers is the “metric
system”, which is officially known as the
“International System” or SI units
(abbreviation for its French term, Système
International).
9. To make sure that scientists from different
parts of the world understand the same
thing when referring to a measurement,
standards have been defined for
measurements of length, time, and mass.
10. Length | 1 m is defined as the distance
travelled by light in a vacuum in
1/299,792,458 second. Based on the
definition that the speed of light is exactly
299,792,458 m/s. (3 x 108 m/s)
LENGTH
11. Time | 1 second is defined as
9,192,631,770 cycles of the microwave
radiation due to the transition between
the two lowest energy states of the
Cesium atom. This is measured from an
atomic clock using this transition.
TIME
12. Mass | 1 kg is defined to be the mass of a
cylinder of platinum-iridium alloy at the
International Bureau ofWeights and
Measures (Sèvres,France).
MASS
14. 1 INCH = 2.54 cm
1 lb = 4.448221615260 newtons
• The second is exactly the same in both the British and the SI
system of units.
• How many inches are there in 3 m?
• How much time would it take for light to travel 10,000 ft?
• How many inches would light travel in 10 fs? (Refer toTable 1 for
the unit prefix related to factors of 10).
• How many newtons of force do you need to lift a 34-lb bag?
(Intuitively, just assume that you need exactly the same amount
of force as the weight of the bag).
16. RULES OF ROUNDING OFF
•KNOW which last digit to keep
•This last digit remains the same if the
next digit is less than 5.
•Increase this last digit if the next digit
is 5 or more.
17. ROUNDING OFF
•In nuclear physics, atomic nuclei with
a magic number of protons or
neutrons are very stable.The seven
most widely recognized magic
numbers as of 2007 are 2, 8, 20, 28,
50, 82, and 126 – round the magic
numbers to the nearest 10.
18. ROUNDING OFF
•2, 8, 20, 28, 50, 82, and 126 – round
the magic numbers to the nearest
10.
25. SIGNIFICANT FIGURES
•*The number of significant figures
refers to all digits to the left of the
decimal point (except zeroes after
the last non-zero digit) and all digits
to the right of the decimal point
(including all zeroes).
26. SCIENTIFIC NOTATION
•*Scientific notation is also called the “powers-
of-ten notation”.This allows one to write only
the significant figures multiplied to 10 with the
appropriate power. As a shorthand notation, we
therefore use only one digit before the decimal
point with the rest of the significant figures
written after the decimal point.
28. EXERCISE
•Perform the following conversions using the correct
number of significant figures in scientific notation:
1. A jeepney tried to overtake a car.The jeepney moves
at 40 km/hour: convert this to the British system (feet
per second)?
2. It takes about 8.0 minutes for light to travel from the
sun to the earth. How far is the sun from the earth (in
meters, in feet)?
3. Let learners perform the calculations in groups (two
to four people per group).
However, a physical
quantity would make sense to everyone when compared to a reference standard. For example, when one says, that his or her height is 1.5 m,
this means that one’s height is 1.5 times a meter stick (or a tape measure that is 1-m long). The meter stick is here considered to be the
reference standard. Thus, stating that one’s height is 1.5 is not as informative.
However, a physical
quantity would make sense to everyone when compared to a reference standard. For example, when one says, that his or her height is 1.5 m,
this means that one’s height is 1.5 times a meter stick (or a tape measure that is 1-m long). The meter stick is here considered to be the
reference standard. Thus, stating that one’s height is 1.5 is not as informative.
However, a physical
quantity would make sense to everyone when compared to a reference standard. For example, when one says, that his or her height is 1.5 m,
this means that one’s height is 1.5 times a meter stick (or a tape measure that is 1-m long). The meter stick is here considered to be the
reference standard. Thus, stating that one’s height is 1.5 is not as informative.
However, a physical
quantity would make sense to everyone when compared to a reference standard. For example, when one says, that his or her height is 1.5 m,
this means that one’s height is 1.5 times a meter stick (or a tape measure that is 1-m long). The meter stick is here considered to be the
reference standard. Thus, stating that one’s height is 1.5 is not as informative.
However, a physical
quantity would make sense to everyone when compared to a reference standard. For example, when one says, that his or her height is 1.5 m,
this means that one’s height is 1.5 times a meter stick (or a tape measure that is 1-m long). The meter stick is here considered to be the
reference standard. Thus, stating that one’s height is 1.5 is not as informative.
However, a physical
quantity would make sense to everyone when compared to a reference standard. For example, when one says, that his or her height is 1.5 m,
this means that one’s height is 1.5 times a meter stick (or a tape measure that is 1-m long). The meter stick is here considered to be the
reference standard. Thus, stating that one’s height is 1.5 is not as informative.
a few countries continue to use the British system of units (e.g., the United States). However, the conversion between the British
system of units and SI units have been defined exactly as follows:
Why do we need to round off numbers? * Estimating a measurement, simplifying a report of a measurement etc.
a few countries continue to use the British system of units (e.g., the United States). However, the conversion between the British
system of units and SI units have been defined exactly as follows:
a few countries continue to use the British system of units (e.g., the United States). However, the conversion between the British
system of units and SI units have been defined exactly as follows:
a few countries continue to use the British system of units (e.g., the United States). However, the conversion between the British
system of units and SI units have been defined exactly as follows:
a few countries continue to use the British system of units (e.g., the United States). However, the conversion between the British
system of units and SI units have been defined exactly as follows:
a few countries continue to use the British system of units (e.g., the United States). However, the conversion between the British
system of units and SI units have been defined exactly as follows:
In the first line, 1.0 cm/20 s was multiplied by the ratio of 1 in to 2.54 cm (which is equal to one). By strategically putting the unit of cm in the
denominator, we are able to remove this unit and retain inches. However, based on the calculator, the conversion involves several digits.
In the second line, we divided 1.0 by 20 and retained two digits and rewrote in terms of a factor 10 - 2. The final answer is then rounded off to
retain two figures.
In performing the conversion, we did two things. We identified the number of significant figures and then rounded off the final answer to retain
this number of figures. For convenience, the final answer is rewritten in scientific notation.
Why do we need to round off numbers? * Estimating a measurement, simplifying a report of a measurement etc.
a few countries continue to use the British system of units (e.g., the United States). However, the conversion between the British
system of units and SI units have been defined exactly as follows:
a few countries continue to use the British system of units (e.g., the United States). However, the conversion between the British
system of units and SI units have been defined exactly as follows:
