DUE in sections October 6 - start of class
DUE as you walk in to or out of LECTURE October 10
or Larson’s mailbox PAT C335 5 pm
2
participation
October 12 - 10:30 am
CLOSES 10:45 am Oct. 12!
Start a few days ahead to get
your 2 attempts at
maximizing your score.
Due today but doesn’t close
until Oct. 10, 11:59 pm. No
penalty for being late on this.
3
Newton’s Laws of motion
Learning Goal
! Relate each of Newton’s laws of motion to
terrestrial and celestial events.
4
Newton’s 1st Law of Motion
! An object resists its change in state: an object at
rest stays at rest and an object in motion stays in
motion unless acted upon by an outside force.
Terrestrial example
Celestial example
Relate each of Newton’s laws of motion to terrestrial and celestial events
5
Newton’s 2nd Law: a = F/m
Solar wind consists
of electrons, protons,
and helium nuclei.
Terrestrial example
Celestial example
Relate each of Newton’s laws of motion to terrestrial and celestial events
6
Newton’s 3rd law
For every action there is an equal and opposite reaction.
Terrestrial example
Relate each of Newton’s laws of motion to terrestrial and celestial events
7
! Relate each of Newton’s laws of motion to terrestrial
and celestial events
» An object resists any form of acceleration. If at rest,
it wants to stay at rest; if in motion, it wants to stay in
motion - at that velocity.
» The acceleration of an object is directly proportional
to the force applied to it and inversely proportional to
its mass.
» Forces come in pairs; for every action there is an
equal and opposite reaction. Unequal forces result in
acceleration.
8
Kepler’s Laws
Learning Goal:
! Relate each of Kepler’s laws of motion to the
orbits of the planets.
9
A Brief Look at Kepler’s Laws
Johannes Kepler (1571 - 1620)
! Relate each of Kepler’s laws of
10
motion to the orbits of the planets.
Demonstrations of Kepler’s Laws #1
! Relate each of Kepler’s laws of
11
motion to the orbits of the planets.
Kepler’s First Law
12
Kepler’s First Law - Eccentricity
13
Take time to answer Question 4
outside of class time.
14
Demonstrations of Kepler’s Laws #2
! Relate each of Kepler’s
laws of motion to the
orbits of 15
the planets.
Kepler’s Second Law
Take time to answer Question 12
outside of class time.
16
Demonstrations of Kepler’s Laws #3
! Relate each of Kepler’s
laws of motion to the
17
orbits of the planets.
Kepler’s Third Law
a = semi-major axis
18
15. Fill in Table 6.1 by calculating the missing data for the planets of our own Solar System. Be
sure to include only the correct number of significant figures.
2 or 3
Finish on your
own outside of class time.
TABLE 6.1
P2 = a3
P = a3/2
or
cube the
value of a
and take
the square
root of that
answer.
The semimajor axes and periods of the planets
of the Solar System.
PLANET
SEMIMAJOR AXIS (AU)
Mercury
0.39
Venus
Earth
1.0
1.9
5.2
Saturn
Uranus
Neptune
244
0.62
Mars
Jupiter
PERIOD (YEARS)
29
19
30
a 3 = P2
a = P2/3
or
square the
value of P
and take
the cube
root of that
answer.
165
Suppose a planet is discovered around a star like the Sun, with a period of 0.2 year.
16. What is the semimajor axis of its orbit? _________
17. How does this compare to the orbits of the planets in our Solar System?
19
Finish this on your own and
turn in to your TA on Thursday
— October 13 —
(discussion & review section)
20