1. See notes.
2. 40 / 0.5 = 80 m/s/s
3. lower acceleration
4. See notes. Tablecloth pull, etc.
5. firearm recoil, etc.
6. Principia Mathematica, 1687.
7. They helped explain retrograde motion - the apparent backwards motion of planets. Really, planets are orbiting the Sun and there are times that some bodies are "behind" -- it's like when you pass someone on the highway and they "appear" to be moving backwards at that time.
8. mass - the amount of stuff (in kg); weight - the gravitational pull on this stuff (in newtons). The weight depends on where you are (in terms of how the gravitational acceleration changes). For example, your weight on the Moon is 1/6 that of Earth.
9. newton; pound
10. W = m g. Weight is depending on the local value of g.
11. Letting g = 10 m/s/s --> 40 m/s, 80 m
>
New questions (and answers):
1. Discuss each of Kepler's 3 laws.
2. At what point in its orbit is the Earth closest to the Sun?
3. At what point in its orbit is the Earth moving fastest?
4. What causes seasons?
5. What is a semi-major axis of orbit (a)?
6. What is an Astronomical Unit (AU)?
7. Consider Jupiter. It's orbit is 5 AU in size (roughly). How long should it take Jupiter to orbit the Sun once? Show how this calculation would be done.
8. What is the period of Earth's orbit around the Sun?
9. What is the size of Earth's orbit (in AU)?
Some more questions from Newton's laws:
10. A 10-kg object is pushed on by a 200-N force. What will be the acceleration?
11. What is the weight of a 100-kg man?
12. Would the answer to 3 be different if he was on the moon? How so?
13. Consider yourself standing on a scale in an elevator. The scale reads your weight. Compared to being at rest, how would the scale reading change (if at all) if the elevator were:
A. Moving with constant velocity upward
B. moving with constant velocity downward
C. Moving with constant acceleration upward
D. Moving with constant acceleration downward
E. If the cable snapped (yikes!) and the elevator were falling
>
1. Discuss each of Kepler's 3 laws.
See notes.
2. At what point in its orbit is the Earth closest to the Sun?
Perihelion, which is approximately January 3-4 each year.
3. At what point in its orbit is the Earth moving fastest?
Same point as 3 above.
4. What causes seasons?
Tilt of Earth's axis.
5. What is a semi-major axis of orbit (a)?
Half the longest distance across the orbital path (ellipse).
6. What is an Astronomical Unit (AU)?
Defined as the semi-major axis of Earth's orbit - roughly 93,000,000 miles - or half the longest width across Earth's orbit.
7. Consider Jupiter. It's orbit is 5 AU in size (roughly). How long should it take Jupiter to orbit the Sun once? Show how this calculation would be done.
5^3 = T^2
So, T = the square root of 125, or around 11 years.
8. What is the period of Earth's orbit around the Sun?
1 year, or approximately 365.25 days.
9. What is the size of Earth's orbit (in AU)?
Defined as 1 AU.
10. F = m a
200 = 10 a
a = 20 m/s/s
11. W = m g
W = 100 g = 980 newtons
12. Yes. The weight would be smaller (1/6 as much, since Moon surface gravity is 1/6 that of Earth).
13. a. your regular weight
b. your regular weight
c. greater than your regular weight
d. less than your regular weight
e. zero! (meaning that you are "weightless")
No comments:
Post a Comment