Title: Charles Hakes
1(No Transcript)
2Chapter 1
3Outline
- Notes
- Kepler Review
- Newtons laws
- Gravity
- Tutoring Berndt 610, 640 late afternoons (Katy,
Shane, Luke)
4Review
- African or European?
- Other favorite answers
- The speed of light.
- I dont know - Im not king!
- My Holy hand grenade blew it up
- 42 (mixing your fiction).
- Im from Oklahoma and have no clue
- for a chimney swallow while hunting mosquitoes.
5Group Exercise
- Assume a comet has a period of 5.2 years, with
eccentricity very close to 1.
6Group Exercise
- Assume a comet has a period of 5.2 years, with
eccentricity very close to 1. - Calculate the semi-major axis.
7Group Exercise
- Assume a comet has a period of 5.2 years, with
eccentricity very close to 1. - Calculate the semi-major axis.
- p2 a3
- What is the major axis?
- What is the maximum distance this comet might
ever get from the Sun? - Include copy of work in your folder.
8Figure 1.20Isaac Newton (1642-1727)
9An iron weight and a styrofoam ball are dropped
from the same height at the same time.
- Which hits the ground first?
- A) The iron weight
- B) The styrofoam ball
- C) They hit at the same time
10Newtons Laws
11Newtons 1st Law
- If there are no external forces on an object,
then - If it is at rest, it will stay that way -
forever. - If it is moving, it will keep doing so at
constant velocity, in a straight line - forever.
12Newtons 1st Law
- Inertia - the natural tendency of an object to
stay at rest, or remain moving with a constant
velocity. - Mass is a quantitative measure of inertia.
13Momentum
- Momentum - the product of mass and velocity.
- momentum mass x velocity
- A concept related to Inertia
- Momentum (both linear and angular) must be
conserved.
14Which object has the most momentum?
- A) A cruise missile
- B) A ship
- C) A glacier
- D) Need more information
15Which object has the most momentum?
- A - A cruise missile
- 1000 kg
- 100m/s
- B - A ship
- 10 million kg 107 kg
- 10 m/s
- C - A glacier
- 1012 kg
- 1 m/day (10-5 m/s)
16Which object has the most momentum?
- A - A cruise missile
- B - A ship
- C - A glacier
17Angular momentum demonstration
18Angular momentum demonstration
- This is why planets move faster closer to the sun.
19Newtons 2nd Law
- The net force on an object is equal to the mass
of the object times the acceleration of the
object - Fnet m a
- The SI units of force are newtons (N).
20Newtons 2nd Law
- Force - something that is capable of changing an
objects state of motion (its velocity) - Fnet - the sum of all forces on an object
- Dynamics - the study of changes in motion and
what causes those changes
21Newtons 2nd Law
22Newtons 3rd Law
23A brick hits a glass window. The brick breaks
the glass, so the magnitude of the force of the
brick on the glass is
- A is greater than the magnitude of the force of
the glass on the brick - B is smaller than the magnitude of the force of
the glass on the brick - C is equal to the magnitude of the force of the
glass on the brick - D none of the preceding
24Newtons 3rd Law
- For every action (force) there is an equal and
opposite reaction (force). - Important note - the action-reaction force pairs
do NOT act on the same object.
25A brick hits a glass window. The brick breaks
the glass, so the magnitude of the force of the
brick on the glass is
- A is greater than the magnitude of the force of
the glass on the brick - B is smaller than the magnitude of the force of
the glass on the brick - C is equal to the magnitude of the force of the
glass on the brick - D none of the preceding
26Gravity
27Figure 1.22Gravity
28Figure 1.24Suns Gravity
29Gravity
- Any object having Mass will exert a gravitational
force on other massive objects. - Force is proportional to mass of each object
- F ? M1 M2
30Gravity
- Any object having Mass will exert a gravitational
force on other massive objects. - Force is proportional to mass of each object
- Force decreases with the square of the distance
between the two objects - F ? M1 M2 / r2
31Figure 1.23Gravitational Force
- Any object having Mass will exert a
gravitational force on other massive objects. - F ? M1 M2 / r2
32Gravity
- Any object having Mass will exert a gravitational
force on other massive objects. - Force is proportional to mass of each object
- Force decreases with the square of the distance
between the two objects - Proportionality constant is G, the universal
gravitational constant - G 6.67x10-11 (N m2/kg2)
- F G M1 M2 / r2
33Gravity
34Newton
- Modification to Keplers 1st Law
- Both the Sun and the planet orbit about the
center of mass of the system.
35Figure 1.25Orbits
36Newton
- Modification to Keplers 3rd Law
- That math law - updated
- P2 (years) a3 (astronomical units)
Mtotal(solar units) - For planets around the Sun, this makes very
little difference except for (even for) Jupiter
(0.1 Msun)
37Which mass pair has the greatest gravitational
force between them?
- 1 A 5Msolar mass and a 4Msolar mass separated by
4 AU. - 2 A 4Msolar mass and a 3Msolar mass separated by
3 AU. - 3 A 3Msolar mass and a 2Msolar mass separated by
2 AU. - 4 A 2Msolar mass and a 1Msolar mass separated by
1 AU.
38Which mass pair has the greatest gravitational
force between them?
- 1 A 5Msolar mass and a 4Msolar mass separated by
4 AU. - 2 A 4Msolar mass and a 3Msolar mass separated by
3 AU. - 3 A 3Msolar mass and a 2Msolar mass separated by
2 AU. - 4 A 2Msolar mass and a 1Msolar mass separated by
1 AU.
39Group Exercise
- Calculate the force between those two masses.
- A 2Msolar mass and a 1Msolar mass separated by 1
AU.
40Three Minute Paper
- Write 1-3 sentences.
- What was the most important thing you learned
today? - What questions do you still have about todays
topics?
41Review
- What was the most important thing you learned?
- A circle is actually a special kind of ellipse
with only one focal point - A square is to a rectangle as a circle is to an
ellipse - The semi-major axis is half of the major axis.
- If the semi-major axis of two bodies is the same,
they take the same amount of time to orbit.
42Review
- What was the most important thing you learned?
- Planets move faster when closer to the sun
- The closer the focus points, the more like a
circle the orbit becomes. - The eccentricity of the ellipse is the ratio of
the distance between the foci to the length of
the major axis.
43Review
- Did not get thrown into the abyss. (i.e.
Remembered Their Monty Python) 3 Other
memorable answers - I dont know - Im not king!
- zero???
- My Holy hand grenade blew it up
- Im from Oklahoma and have no clue
- for a chimney swallow while hunting mosquitoes.