Welcome to PHY 183 Physics for Scientists and Engineers

Meaning of the picture ?

Lecturer:MSc: Dương Hiếu Đẩu Vice Dean of COS Head of Physics DeptEmail: dhieudau@ctu.edu.vnTel: 84.71. 832061

PHY 183

PHY 183 - Program Physics for Scientists and Engineers

Chapter 1 KINEMATICS 7/5Chapter 2 DYNAMICS 7/5 Chapter 3 WORK AND ENERGY 6/4 Chapter 4 ROTATIONAL MOTION 6/4 The first test 40% (2)Chapter 5 PERIODIC MOTION 5/3Chapter 6 WAVE MOTION 5/3 Chapter 7 FLUIDS AND THERMAL PHYSICS

5/3 Chapter 8 GAS LAWS AND KINETIC THEORY

5/3Chapter 9 LIQUID PHASE 6/4 The final examination 60%

1- ELEMENTARY MECHANICS &THERMODYNAMICS

John W. Norbury2- 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

Download books and communications

1. Lecturing. 25 H

2. Doing exercises. 18 H

3. Reading books and group discussions. 10

H1. Seminars. 05 H 2. Testing. 02 HYou are free to ask the teacher for your

understanding

1. Measurements & units2. Scalars & vectors3. Displacement, Velocity and

acceleration4. Relative velocity.5. Motion in two dimensions and

in three dimensions6. Special case: Gravity

Part 1

Measurements

Units of Measurement

Express this experiment ?

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

Which one can be used for house?

Some Tools for Measurement

Thermometer

Measuring cup,Graduated cylinder

Watch

Scale

Give the names for these tools

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

EX: Use a microscope

to determine the size

of a virus (5 m)

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 2 Ibs 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 is1) 1.5 yards 2) 6 feet 3) 2 meters

B. The volume of two bottles is1) 1 liters 2) 1 quart 3) 2 pints

C. The mass of a lemon is1) 12 ounces 2) 145 grams 3) 0.6 pounds

Solution

A. John’s height is

3) 2 meters

B. The volume of two bottles is1) 1 liter

C. The mass of a lemon is

2) 145 grams

Learn by heart

Volume

Name symbol = m Name symbol = m

Learn by heart

X 0C= (X+273) 0K = (0,8X) 0R = = (1,8X+32) 0F

Name =Kg Name =Kg

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…

A =5cm

B =5cm

C =7.07cm

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…)

A B = 0A B = 0

A B = 0 A B = 0

A B = |A| |B| cos()

|A B| = |A| |B| sin()

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.

A î = Ax

î

A

A x

Ay

A B = (A )(B ) + (A )(B )x yx y

cos BA BA

Learning Check

The product of two vector A and B (see figure) is

A =5cm

B =5cm A . B = |A| |B| cos() =0

|A B| = |A| |B| sin()= 25

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

-ri

∆r

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.

a

• 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 ?