GD HN: ST BG vật lý đại cương

Welcome to PHYsic 183
Physics for Scientists and Engineers
http://thucpham.dncot.edu.vn/gi%C3%A1otr%C3%ACnht%C3%A0ili%E1%BB%87u/tabid/57/language/vi-VN/Default.aspx
Lecturer:
MSc: Dương Hiếu Đẩu
Vice Dean of COS
Head of Physics Dept
[email protected]
Tel: 84.71. 832061
PHY 183
PHY 183
Physics for Scientists and Engineers

Chapter 1 KINEMATICS 7(5 study hours)
Chapter 2 DYNAMICS 7(5 study hours)
Chapter 3 WORK AND ENERGY 6(4 study hours)
Chapter 4 ROTATIONAL MOTION 6(4 study hours)
The first test 40%
Chapter 5 PERIODIC MOTION 6(4 study hours)
Chapter 6 WAVE MOTION 6(4 study hours)
Chapter 7 FLUIDS AND THERMAL PHYSICS
6(4 study hours)
Chapter 8 GAS LAWS AND KINETIC THEORY
6(4 study hours)
Chapter 9 LIQUID PHASE 6(4 study hours)
The final examination 60%
1- ELEMENTARY MECHANICS &THERMODYNAMICS
John W. Norbury
2- Cơ Nhiệt - Đại cương.
Nguyễn Thành Vấn & Dương Hiếu Đẩu
3- Fundamentals of Physics (Fourth edition) David Halliday, Robert Resnick, Jearl Walker
4- Principles of Physics
Frank J. Blatt.
Reference books:
Download books and communications
Lecturing. 25 H
St do exercises. 18 H
Reading books and
group discussion. 10 H
Seminar. 05 H
Test. 02 H
You are free to ask the teacher for understanding
Teaching method
Measurements & units
Scalars & vectors
Displacement, Velocity and acceleration
Relative velocity.
Motion in two dimensions and in three dimensions
Special case: gravity
CHAPTER 1 KINEMATICS (5/7)
Part 1
Measurements

Units of Measurement

Measurement
You are making a measurement when you
Check your weight * Check your height
Read your watch * Take your temperature
Looking your face from a mirror
Listening to your voice
What kinds of measurements did you make today?

Standards of Measurement
When we measure, we use a measuring tool to compare some dimension of an object to a standard.
EX: Use a ruler
determine three
dimensions of a house
Some Tools for Measurement

Thermometer
Measuring cup, Graduated cylinder
Watch
Scale
Learning Check
From the previous slide, state the tool (s) you would use to measure
A. temperature ____________________
B. volume ____________________
____________________
C. time ____________________
D. weight ____________________
thermometer
measuring cup, graduated cylinder
watch
scale
Measurement in Physics
In Physics we
do experiments
measure quantities
use numbers to report measurements

Learning Check
What are some international units that are used to measure each of the following?
A. length
B. volume
C. weight
D. temperature
Solution
Some possible answers are
A. length inch, foot, yard, mile
B. volume teaspoon, gallon (4,54L England-3,78L US), pint (0.58 L), quart(1.14 L)
C. weight ounce, pound (lb), ton
D. temperature °F °K °R
Metric System (SI)
System of international measurements

Is a decimal system based on 10
Used in most of the world
Used by scientists and hospitals
What are fundamental scientific SI unit ?
Stating a Measurement
In every measurement there is a
Number followed by a
Unit from measuring device
Learning Check
What is the unit of measurement in each of the following examples?

A. The patient’s temperature is 102°F.
B. The sack holds 5 lbs of potatoes.
C. It is 8 miles from your house to school.
D. The bottle holds 2 L of orange soda.


Solution
A. °F (degrees Fahrenheit)
B. lbs (pounds)
C. miles
D. L (liters)
Learning Check
Identify the measurement in metric units.
A. John’s height is
1) 1.5 yards 2) 6 feet 3) 2 meters

B. The volume of two bottles is
1) 1 liters 2) 1 quart 3) 2 pints

C. The mass of a lemon is
1) 12 ounces 2) 145 grams 3) 0.6 pounds
Solution
A. John’s height is
3) 2 meters

B. The volume of two bottles is
1) 1 liter

C. The mass of a lemon is
2) 145 grams
Learn by heart
Learn by heart
X 0C= (X+273) 0K = (0,8X) 0R = = (1,8X+32) 0F
Learning Check
Your temperature is 40 0C, it equals to..
A. 314 0K
B. 32 0R
C. 104 0F
D. All are the same
System based on 10
Scientific Notation
Learning Check
Part 2
Vectors and scales


Learning Check
The sum of two vector A and B (see figure) is C…
Multiplication of vectors
There are two common ways to multiply vectors
“Scalar or dot product”: Result is a scalar

“Vector or cross product”: Result is a vector (not now…)
We can write vector without arrow
Scalar product
Useful for performing projections.
Calculation is simple in terms of components.
Calculation is easy in terms of magnitudes and relative angles.
Learning Check
The product of two vector A and B (see figure) is
Part 3
Displacement, Velocity and Acceleration


How can we determine
a car M is running or not ?
A. Use a certain point O (at rest)
B. Measure r = OM
C. If OM unchanged  M at rest
D. OM changed  car is moving
0
M
0M
Displacement
The position of an object is described by its position vector, r
The displacement of the object is defined as the change in its position (final –initial)
∆r = rf - ri
Average Velocity
The average velocity is the ratio of the displacement to the time interval for the displacement
The direction of the average velocity is in the direction of the displacement vector, ∆r
The average velocity between points is independent of the path taken
Instantaneous Velocity
The instantaneous velocity is the limit of the average velocity as ∆t approaches zero
The direction of the instantaneous velocity is along a line that is tangent to the path of the particle’s direction of motion.
v
The magnitude of the instantaneous velocity vector is the speed. (The speed is a scalar quantity)
Average Acceleration
The average acceleration of a particle as it moves is defined as the change in the instantaneous velocity vector divided by the time interval during which that change occurs.
The average acceleration is a vector quantity directed along ∆v
Instantaneous Acceleration
The instantaneous acceleration is the limit of the average acceleration as ∆v/∆t approaches zero

The instantaneous acceleration is a vector with components parallel (tangential) and/or perpendicular (radial) to the tangent of the path (will see in Chapter 4)

Producing an Acceleration
Various changes in a particle’s motion may produce an acceleration
The magnitude of the velocity vector may change
The direction of the velocity vector may change
(Even if the magnitude remains constant)
Both may change simultaneously
Exercises of today’s lecture
Make the figure to show this moving
What is displacement of a train from staring point to point at 3 seconds after ?
What is the velocity and acceleration of a train?? from staring point to point at 3 seconds after ?