Download STUDY GUIDE FOR CHAPTER 1

STUDY GUIDE FOR CHAPTER 4
The following is a list of topics and subtopics.
I. Dynamics
A. You should know the following basic definitions in physics
1. mass
2. weight
3. velocity
4. acceleration
5. force
6. angular momentum, conservation of angular momentum
7. Questions:
a. What is the difference between mass and weight?
b. Explain Kepler’s 2nd law using conservation of angular momentum.
B. You should know Newton’s three laws by content and by number.
1. Explain Kepler’s 2nd law using Newton’s 2nd law.
2. Why does an object moving in a circular orbit at a constant speed need to have a force
act on it in order to have this motion?
3. What is the main way that we have so far been able to detect planets around other stars?
Why does this work?
II. Energy
A. Conservation
1. What does energy conservation mean?
2. Can energy ever be created or destroyed?
B. Types of energy
1. Kinetic: E = ½ m v2.
a. What is m? What is v?
b. If a baseball is thrown at 100 mi/hr does it have a lot of kinetic energy? Why?
c. If the spaceshuttle is being hauled to the launchpad at 1 mi/hr does it have a lot of
kinetic energy? Why?
2. Gravitational potential energy
a. What is potential energy?
b. Why is it that the higher above the ground an object is, the more gravitational potential
energy it has?
c. Would an object above the surface of the Moon have gravitational potential energy?
3. What is radiative energy?
4. Thermal energy
a. What type of energy is thermal energy?
b. How is it related to temperature?
c. What is heat?
5. Matter
a. Is matter a form of energy?
b. If so what is the relationship between matter and energy?
III. Gravity
A. You should understand Newton’s law of gravity.
1. Is gravity an attractive or repulsive force?
2. What objects feel this force? What objects exert this force on other objects?
3. What makes the gravitational force increase? Decrease?
B. Newton’s version of Kepler’s laws
1. Newton’s version of Kepler’s laws work any time the main force on an object is the
gravitational force exerted by another object. This is true for the Moon going around
the Earth, double star systems, etc.
2. What other types of orbits does Newton’s version allow? What is different about these
orbits than the elliptical ones Kepler found?
3. What is Newton’s version of Kepler’s 3rd law particularly good for?
C. Escape Speed and Energy of Orbits
1. What are the two types of energy occur for an orbiting object.
2. What is the escape speed?
3. What makes the escape speed larger? Smaller?
D. Tides
1. Why are there two tidal bulges? Where are they in relation to the Moon?
2. What are neap tides and spring tides? When do they occur? Why do they occur?
3. You should understand why the Earth’s rotation rate is slowing down.
a. As the Earth rotates the places of high and low tides constantly changes.
b. This is opposed by friction and friction then causes heat to be generated
c. The energy for the heat must come from somewhere. It comes from the Earth’s
rotation. What kind of energy is the energy due to the Earth’s rotation?
d. Thus the Earth’s rotation rate slows down.
4. Conservation of angular momentum for the Earth-Moon system means the angular
momentum of the Moon must increase to compensate for that lost by the Earth’s
rotation slowing down. This causes the Moon to get farther away from the Earth.
5. This process also happened long ago on the Moon and the Moon’s rotation rate slowed
until it always shows the same face to the Earth. Then the position of the tidal bulge on
the Moon does not change much and this minimized the effect of friction. Thus the
Moon continues to show the same face to the Earth.