Chapters from the textbook:
$Introduction, motion, force,
energy - Chapters 1 - 7
$Structure of matter -
$Thermodynamics - Chapters 13
$Astrophysics and cosmology - Chapters 32-33.
FORMULAS AND LAWS:
x - Displacement (distance)
v - Velocity
a - Acceleration
t - Time
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
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
Kinetic Energy = ½mv2 Gravitational Potential Energy = Weight x height = mgh
Energy Heat and Temperature : Thermodynamics
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
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.
8max = 2.9x10-3/T.
8max in meters – wavelength of the maximum of the spectral distribution.
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.