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Secondary 4 Physics Introduction
Dear S.4 physics students,
I highly recommend you to read this PowerPoint file before attending your first physics lesson in 2003 – 2004.
Mr. Ma
For any problems, send an e-mail to Mr. Ma at [email protected]
Introduction to Physics
What is Physics ? Why do we study Physics ? Content of HKCEE Physics How can we study Physics well ? Basic mathematical skills: Treatment of
significant figures and Graphs
For any problems, send an e-mail to Mr. Ma at [email protected]
What is Physics ? Physics is the quantitative (that is, involving “data
analysis”) study of the laws of nature ( 大自然定律 ) using scientific methods.
We learn physics based on
(1) Experimental work: It provides us with raw data, then we look for relations among
the data, and try to guess general laws.
(2) Theoretical ( 理論的 ) work: To apply the physical laws to different situations
and hence solve problems.
For any problems, send an e-mail to Mr. Ma at [email protected]
Why do we study physics ?1. To satisfy our curiosity about nature2. To provide us with a good training in working systematically and scientifically
(I am sure that you would agree with this advantage of studying physics. I hope you will enjoy learning
physics !)3. To upgrade our living standard, because
grasping physics (as an important branch of Science) -> high Technology
-> better living in the Society
For any problems, send an e-mail to Mr. Ma at [email protected]
Content of S.4 – S.5 Physics1. Mechanics (力學 )
- a study of motion: e.g. What can you say about the motion of a falling object ?
2. Heat (熱學 )
l - a study of heat transfer: e.g. What is the final temperature if a cup of water at 20oC mixes
with another identical cup of water at 400C ?
3. Waves (波動學 )
- a study of wave motion (which is one way of energy transfer), e.g. radio waves, water waves 4. Electricity (電學 ) & magnetism (磁學 )
5. Atomic Physics (原子物理學 )
- a study of atomic structure and radioactivity
For any problems, send an e-mail to Mr. Ma at [email protected]
How to study physics better ?After learning some physics, ask yourself :
1. What are the aims (目標 ) of that chapter ?2. What tools and methods have you got to achieve
the above aims ?- Tools mean “physical quantities”, e.g. time.- Methods mean “physical laws”, “experimental
approach”, “logical thinking skills” and “mathematical skills”.3. Practise more in solving problems, and try to ask
more questions from the problems:e.g. If a problem is related to a “falling” ball, you may ask “what happens when the ball is rising ?”.
For any problems, send an e-mail to Mr. Ma at [email protected]
Example:The volume of a rectangular block is: V = abc, where a, b and c are its length, width and height respectively.Let a = 15.70 cm, b = 4.80 cm and c = 2.0 cm. Find V.
Basic mathematical skills:Treatment of significant figures
1.The number of significant figures reflects the accuracy of a measurement.2.The final result is governed by the least accurate measurement.
Solution:When we calculate 15.7 x 4.8 x 2 by using a calculator, it displays 150.72. Then, is V equal to 150.72 ?NO, because the least accurate measurement is “c” (only 2 sig. fig.), so V should be expressed in 2 sig. fig. Hence, V = 150 cm3 (corrected to 2 sig. fig.).
For any problems, send an e-mail to Mr. Ma at [email protected]
Basic mathematical skills:Graphs
y
x
y is directly proportional to x.
p
q
p increases linearly with q.
For any problems, send an e-mail to Mr. Ma at [email protected]
Basic mathematical skills:Graphs
y
1/x
y is directly proportional to 1/x.
y
x
y is inversely proportional to x.
