Download Name:_____________________________________ ... Astro 1 (Levine) F2015 Kepler, Gravity, Light

KEY
Name:_____________________________________
Astro 1 (Levine)
F2015
Score: ________/23
Kepler, Gravity, Light
1. The table below lists the orbital eccentricities and semi-major axes for objects in the solar
system. Recall that an ellipse with an eccentricity of 0 is perfectly circular, whereas an orbit
shaped like this !
probably has a large eccentricity between 0.8 and 0.9.
Object
Type
Eccentricity of
orbit
Semi-major axis
(a)
A
Earth
planet
0.016
1.0 AU
B
Eris
dwarf planet
0.442
68 AU
C Halley’s Comet comet
0.967
18 AU
D Mercury
planet
0.206
0.39 AU
E
Trans-neptunian object 0.853
520 AU
Sedna
a) Using the table, write the letter (A-E) below the orbital shape which is most likely
similar to that of the listed object. (2 points)
!
A
____
D
____
B
_____
E
______
C
_____
b) Rank the orbital period (time to complete one full orbit or the “year”) of the objects in the
table from longest period to shortest period. (2 points)
E
B
C
A
D
Longest: _____ _____
_____
____
____ :Shortest
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2. The figure below shows a comet traveling in an elliptical orbit around the Sun. The comet is
shown as it moves through four different segments of its orbit (labeled A, B, C, and D).
During each segment of the orbit the comet sweeps out the triangular shaped area shaded in
gray. Assume each of the shaded triangular shaped areas has the same size. (2 points each)
a) Rank the time it took (from greatest to least) for the comet to move along each of the
segments (A - D) of the orbit.
Greatest 1_______ 2_______ 3_______ 4_______ Least
X
Or, the time to travel each segment would be the same. ______
b) Rank the distance (from greatest to least) the comet traveled during each of the segments
(A –D) of the orbit.
B
A
C
D
Greatest 1_______ 2_______ 3_______ 4_______ Least
Or, the distance traveled during each segment would be the same. ______
c) Rank the speed (from greatest to least) the comet is traveling at during each of the
segments (A –D) of the orbit.
B
A
C
D
Greatest 1_______ 2_______ 3_______ 4_______ Least
Or, the distance traveled during each segment would be the same. ______
2
3. Ranking. 2 points each
A. Xrays
B. Visible Light
C. Radio Waves
D. Gamma Rays
E. Ultraviolet light
F. Infrared Light
G. Microwaves
a) Rank them in order of wavelength, from shortest to longest:
D
A
E
B
F
G C____ Longest
Shortest ____ ____ ____ ____ ____ ____
Or, all have the same wavelength______________
b) Rank them in order of frequency, from lowest to highest:
C ____
G ____
F ____
B ____
E ____
A
Lowest ____
D Highest
____
Or, all have the same frequency ______________
c) Rank them in order of energy (per photon) from least to greatest:
C
G
F
B
E
A
Least ____ ____ ____ ____ ____ ____
D
____ Greatest
Or, all have the same energy ______________
d) Rank them in order of speed (in empty space), from slowest to fastest:
Slowest ____ ____ ____ ____ ____ ____
____ Fastest
X
Or, all have the same speed ______________
4. Use the internet and/or your text book to answer the following (1 point each)
390 nm to _____
700 nm
a) What is the wavelength range for visible light? _____
0.00002
b) This is about _____________________
inches (you can use a conversion tool such as
http://www.convertunits.com/from/inches/to/nm if you want).
c) Look up the average thickness of a human hair. Visible light has a wavelength (circle
one) much smaller about the same as much larger than a human hair
x
3
5. The table below shows the masses and distances between four different pairs of stars. The
masses and distances are in arbitrary units. (2 points)
Case
Mass of Star 1
distance between Star 1 & Star 2
Mass of Star 2
A
4
2
2
B
2
2
8
C
8
4
4
D
1
3
5
Rank from greatest to least the strength of the gravitational force exerted between the pairs of
stars A-D.
B
A
C
D
Greatest _____ _____ _______ _______ Least
Or, the strength of the gravitational force exerted between each pair of stars is the same ______
for A mxM is 8 and distance is 2 (force is proportional to 8/4=2)
for B mxM is 16 and distance is still 2 so B has greater force than A
(force is proportional to 16/4=4)
for C mxM is 32 and distance is 4 mass is twice B but distance is twice B
so force is only half, or same as A (A and C can be in either order)(Force
is proportional to 32/16=2)
for D mxM is 5 and distance is 3 Mass is smaller than for A and distance
is large, must be less than A (Force is proportional to 5/9 <1)
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