Chapters from the textbook:

$Introduction, motion, force, energy - Chapters 1 - 7
 

$Structure of matter - Chapter 11
 

$Thermodynamics - Chapters 13 - 15
 

$Astrophysics and cosmology - Chapters 32-33.


 

FORMULAS AND LAWS:

Motion:

x - Displacement (distance)

v - Velocity

a - Acceleration

t - Time

 

 

Newton's Laws:

1st. Every body continues in its state of rest or of uniform speed in a straight line unless it is compelled to change that state by forces acting on it.

2nd. The acceleration of a body is directly proportional to the net force acting on it and inversely proportional to its mass. The direction of the acceleration is in the direction of the applied force.

3rd. Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first.

 

Weight = mg

 

Circular Motion

F - Centripetal Force

 

Law of Universal Gravitation:

Every body in the universe is attracted to every other body with a force that is proportional to the product of their masses and inversely proportional to the square of the distance between them. The force acts along the line joining the two bodies.

G = 6.7x10-11 Nm2/kg2

Work = Force x distance

Power = work/time  = energy transformed/time

 

Energy:

 

Kinetic Energy = mv2                            Gravitational Potential Energy = Weight x height = mgh

Energy Heat and Temperature : Thermodynamics

DEFINITIONS:

 

1st. Law of Thermodynamics - The change in internal energy of a closed system is equal to the heat added to the system minus the work done by the system -

 

2nd. Law - Alternative difinitions:
 

-Heat flows spontaneously from a hot object to a cold object-
 

- No device is possible whose sole effect is to transform a given amount of heat completely into work.-
 

- Natural processes tend to proceed toward a state of greater disorder-

 

Entropy - measure of disorder @ Number of ways that energy can partition.
 

Work  Heat  Energy---4180 Joule = 1 Cal = 1 Kcal.

 

Temperature - Measure of internal energy.

 

Temperature Scales: F = 32 + (9/5)C

K = 273 + C

 

Heating an Object: Q = mc(T - T0)

(m - mass, c - specific heat, T - final temperature, T0 - initial temperature)

 

Maximum Efficiency of Heat Engine = (Work output/ Heat input) = 1 - Tc/TH

(Tc - Temperature (Kelvin ) of cold reservoir, TH - that of hot reservoir)

 

Ideal Gas Law: PV = NkT

(P - pressure, V - volume, N - No. of molecules, T - Absolute (Kelvin) Temperature, k - Boltzmann Constant = 1.38x10-23 Joule/K) 

ENERGY, ELECTROMAGNETIC RADIATION:

Earth and Cosmological Energy Balance




 

 

 

 Speed of light – c=3x108 m/sec.

 

C = 8/T        8  wavelength; T – period; c – speed of light

 

f = 1/T frequency ;  c= f 8

 

1nm = 10 Angstroms = 10-3  micrometers = 10-9m= 10-7cm.

 

The Electromagnetic Spectrum:

 




 

 

Stefan Boltzman Law:

 

For ideal blackbody the total rate of emission is:

Pe = sAT4

 

T – temperature in 0K; A – area in m2; s – Stefan Boltzman constant = 5.67x10-8W/m2.0K

Pe – total emitted power in watts.

 

Wien Law:

 

8max = 2.9x10-3/T.

 8max in meters – wavelength of the maximum of the spectral distribution.

 

Hubble’s Law:

 

V = Hd

 

V – velocity of galaxies moving away from us; d – distance of the galaxies;

H – Hubble’s constant = 15km/sec per million light year of distance.

 

Issues to discuss:

 

       The greenhouse effect

       Earth’s energy balance

       The cosmological energy balance – The microwaves background radiation as a probe of the beginning of the universe.