Why Can't I Solve This Kepler's Law Problem Correctly?

  • Context: Graduate 
  • Thread starter Thread starter takoma
  • Start date Start date
  • Tags Tags
    Law
takoma
Messages
4
Reaction score
0
For some reason, I just can't seem to get this problem right even though I go through it tons of times and I earnestly believe that my answer is correct, but I guess not.

http://img.photobucket.com/albums/v45/takomastock/640ddd43.jpg"

"Use Kepler's Laws to determine the comparison between various items shown in the figure. Assume the figure is drawn to scale.
(Select G-Greater than, L-Less than, E-Equal to, If the first is G and the rest E, enter GEEEE)."

A) A planet with half the average distance to the star would have ... half the period.
B) If area 1 and 3 are equal the time to go from D to E is ... the time to go from A to B
C) The speed at A ... the speed at D
D) The planets's average speed between D and E is ... the average speed between A and B
E) Time to go from B to C is ... time from A to B

I've come up with all these answers and all are wrong. I even narrowed it down to believe that the last 4 answers are "EGLE", but it seems it's wrong.

These are all the possibilities I've come up with, and nope. Still incorrect.

EEGEG

LEGEG

EEGLG

EEGLE

LEGLE

GEGLE

GEGLG

--

Please freaking enlighten me. :cry:
 
Last edited by a moderator:
Astronomy news on Phys.org
takoma said:
For some reason, I just can't seem to get this problem right even though I go through it tons of times and I earnestly believe that my answer is correct, but I guess not.

http://img.photobucket.com/albums/v45/takomastock/640ddd43.jpg"

"Use Kepler's Laws to determine the comparison between various items shown in the figure. Assume the figure is drawn to scale.
(Select G-Greater than, L-Less than, E-Equal to, If the first is G and the rest E, enter GEEEE)."

A) A planet with half the average distance to the star would have ... half the period.
B) If area 1 and 3 are equal the time to go from D to E is ... the time to go from A to B
C) The speed at A ... the speed at D
D) The planets's average speed between D and E is ... the average speed between A and B
E) Time to go from B to C is ... time from A to B

I've come up with all these answers and all are wrong. I even narrowed it down to believe that the last 4 answers are "EGLE", but it seems it's wrong.

These are all the possibilities I've come up with, and nope. Still incorrect.

EEGEG

LEGEG

EEGLG

EEGLE

LEGLE

GEGLE

GEGLG

--

Please freaking enlighten me. :cry:

1) T^2 = a^3 so as the semimajor axis is cut in half...the period moves down faster than half (L)
B) they must be the same because equal areas are swept out during equal times. (E)
C) (G) seems you understand this
D) Look at the distance traveled in the same period of time...also, when an orbiting object is closer, its average speed is increased(L)
E) the object's speed slows down as it moves away(G)

I believe this is correct...please correct me if I'm wrong
 
Last edited by a moderator:

Similar threads

  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 9 ·
Replies
9
Views
3K
Replies
5
Views
2K
  • · Replies 11 ·
Replies
11
Views
5K
Replies
10
Views
3K
Replies
7
Views
6K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K
Replies
17
Views
4K
  • · Replies 2 ·
Replies
2
Views
6K