phy101 lecture 1

PHY101: Introduction to Physics I

Monsoon Semester 2015-16

Department of Physics, School of Natural Sciences,Shiv Nadar University

Aims of this course

To bridge the gap between the 10+2 and standard undergraduate levels.

To develop an understanding of basic Physics laws and skills to apply various physical concepts to science and engineering through problem

solving.

Course outline and syllabus

Mechanics: Reference frames and Coordinate systems

Newton’s laws of motion in vector notation

Conservation of energy

Application of Newton’s laws of motion

Dynamical stability of systems: Potential energy

diagram

Collisions: Impulse, conservation of energy and

linear

momentum

Conservation of angular momentum and rotation of

rigid

bodies in plane

Thermal Physics: Averages, probability and probability distributions

Thermal equilibrium and macroscopic variables: Pressure of an ideal gas from Newton’s laws - the kinetic theory of gases. Maxwell’s velocity distribution

Laws of Thermodynamics and the statistical origin of the second law of thermodynamics

Application of thermodynamics: Efficiency of heat engines and air-conditioners, Thermodynamics of batteries and rubber bands

Competency

At the end of the course you should be able to:

Understand the laws of Newtonian mechanics and apply these laws to study kinematics of many body and rigid body systems.

Demonstrate the understanding of Kinetic theory of gases, Laws of Thermodynamics, Concept of entropy etc., and apply this understanding to various physical systems.

Course MaterialsText/Reference books:1. An Introduction to Mechanics, by Kleppner and Kolenkow2. Physics for Scientists and Engineers with Modern Physics, by J. W. Jewett, R. A. Serway3. Fundamentals of Physics, by Resnick, Halliday and Walker4. Feynman Lecture Series, Vols. 1 & 3

Other relevant materialsVideos, animations, web sources

Assessment scheme

One mid semester exam: 30% (24-26th Sept)

2 quizzes: 30% (15% each) (28th Aug & 2nd Nov)

End-semester examination: 40% (1st Week Dec)

Minimum passing marks (Abs. scale): 40%

Note: Any unfair means will invite “F” grade

Syllabus for the examinations

• Mid Sems.– Topics covered up to one day before the

scheduled examination day• End Sems.– Topic covered up to mid sems. exam: 40-50 %– Topic covered from mid sems. to the end sems.

Exam: 50-60%• Each Quiz: 10-15 min

Physics is the most fundamental and all-inclusive of the sciences, and has had a profound effect on all scientific development.

-RICHARD FEYNMAN

Motivation

Why bother to learn concepts and principles which were proposed or formulated centuries ago?

http://www.diplomaframe.com/about-us/press-releases/press-release-may-22-2009.aspx

Physics is all around us, all the time

Matter and Energy• All the objects around us are called bodies

• Matter is the material of which all bodies are made of

• Energy is that invisible agency which can bring internal or external change in matter

Coal can be crushed into powder

http://www.hammermills.com/size-reduction-product-categories-schutte-buffalo-hammermill/hammer-mills/industrial-hammer-mills/wa-series-hammer-mill

http://www.123rf.com/photo_5551459_coal-miner-at-work-with-pneumatic-drill.html

http://arizonamechanicalengineering.com/Solid%20Fuel%20Combustion%20Engineering.htm

Mechanical energy has brought change in matter

Heat energy of the fire has brought change in matter

All natural phenomena are the effects of action of the energy in matter

Properties of Matter

• Occupies space• Offers resistance when any force is applied to

displace it or stop when moving– Properties of inertia

• Transfer momentum, which makes another body to change its motion by colliding

• Feels gravitational attraction

Properties of Energy

• Energy brings changes in the matter• Matter cannot undergo any change by itself• In nature, 3 classes of change can be seen:– Change in position (moving car)– Change in condition/state (boiling off of water)– Change in constitution/type (Burning of coal)

During the change, neither Matter nor Energy suffers from destruction

Physics is developed by learning how to measure the quantities involved

What is quantity?

It is used to mean any thing that can be measured such as length, time, temperature, pressure, etc.

Laws and Principles

They represent the relation between different physical quantities

Example: Force = mass x acceleration

Each quantity is measured with its own unit, by comparison with a standard

Unit is an universal name assigned for measuring a quantity

1 kg1 m1 hr

Example:

Physical quantity = Numerical value + Unit

There are several physical quantities, BUT they are not independent

Example: Speed = Length/Time = 20 m/5 s

= 4 m/s

Physical quantities are expressed by 3 fundamental quantities:

Length [L] Mass [M]Time [T]

Example: momentum = mass x velocity = mass x displacement/time = [MLT-1]

Dimensions of Physical quantities

Dimension of a quantity signifies its physical nature

Derived Units

Units derived from Fundamental units

Example: Area of a plane [A] = [L]2 2 Dimension

Volume [V] = [L]3 3 Dimension

What would be the dimension of density which is mass/volume?

What’s about acceleration?

[ML-3]

[LT-2]

Dimensional analysis

The time period t of small oscillations in a simple pendulum of length l is given by (g is the acceleration due to gravity(a) , (b) (c)

What is Scientific notation?To express very large and small quantities using power of 10

Example:35000000 m = 3.5 x 107 m0.000 000 49 m = 4.9 x 10-7 m

Using Prefix1.29 x 109 W = 1.27 GW2.53 x 10-9 s = 2.53 ns

“Fundamentals of Physics” by Halliday and Resnick

Order of Magnitude

Examples:Mean diameter of Sun, DS 1392684 kmMean diameter of Earth, DE 12742 km

DS/DE 1.4 x 106/1.3 x 104 ~ 102

The mean diameter of Sun is two orders of magnitude larger than the Earth

The universe is 13.8 billion years old. The average human life expectancy is ~70 years. How many orders of magnitude is the former larger than the latter.

(a) 103, (b) 105, (c) 108, (d) 1011

Ans. 13.8 x 109/70 2 x 108 ~ 108

Elementary calculus

http://en.wikipedia.org/wiki/File:Graph_of_sliding_derivative_line.gif

Show

Hint: Consider a + bx = z

http://en.wikipedia.org/wiki/File:Integral_example.svg

The definite integral can be interpreted as area (signed)

under the curve