Transcript Newton`s first law

INNER PLANETS
OUTER PLANETS
IR
picture
105
ly
Scorpius
constellation
Galactic
center
THE LOCAL GROUP
106 ly
ANDROMEDA
2x106 LY from us
GALACTIC STRUCTURES
SPIRAL 30%
LENTICULAR
ELLIPTICAL -majority
IRREGULAR
ACTIVE GALAXIES
RF JETS AND BLACK HOLE – NGC4261
GALAXY CLUSTERS
VIRGO
COMA
FORMAX
RED SHIFT SURVEYS TO 150 Mpc, ~2% to edge
Filaments
and
Sheet-like
Structures
And
Bubble-like
voids
EPICYCLES - COPERNICUS
KEPLER’S LAWS
The orbits of the planets are ellipses, with the Sun at one focus of the ellipse.
The line joining the planet to the Sun sweeps out equal areas in equal times as the planet travels around the ellipse.
Galileo’s
drawing
Huyghen’s
drawing
Hubble
image
KEY QUESTIONS:
• WHY SIX PLANETS ?
• WHAT CONTROLS THE SIZE OF THEIR ORBITS
KEPLER MYSTERIUM COSMOGRAHICUM
A precursor to cosmographical dissertations, containing the cosmic
mystery of the admirable proportions of the Celestial Spheres, and
of the True and Proper Causes of their Numbers, Sizes, and
Periodic Motions of the Heavens, Demonstrated by the Five Regular
Geometric Solids
Numbers
p =3.14159……
f = 1.6180339…. Golden ratio, Golden number, Golden Section
A
C
B
AB/AC=AC/CB
Bode’ Law
Distances of planets from Sun
M .39, V .72, E 1.0, Mars 1.5, J 5.2, SAT 9.5, UR 19, N 30, PL 39
Start with 0,3,6,12,24,48,96,192,384
Add 4 and divide by 10
.4,.7,1.0,1.6,2.8,5.2,10,19.6,38.8
Missed Neptune and no planet at 2.8
Asteroid belt -> rocks (40000) few km size
Newton’s laws
• Newton’s laws of motion
• Frames of reference
• Newton’s law of Gravitation
I: NEWTON’S LAWS OF
MOTION
Begin by stating Newton’s laws:
Newton’s first law (N1) – If a body is not acted
upon by any forces, then its velocity, v, remains
constant
Note:
– N1 sweeps away the idea of “being at rest” as a natural
state.
Newton’s 2nd law (N2) – If a body of mass M is
acted upon by a force F, then its acceleration a
is given by F=Ma
Note
– N2 defines “inertial mass” as the degree by which a
body resists being accelerated by a force.
– Another way of saying this is that force = rate of
change of momentum (rate of change of mv).
Newton’s 3rd law (N3) - If body A exerts force F
on body B, the body B exerts a force –F on
body A.