astronomy /AN

Astronomy Ranking Task:
Gravity
Exercise #1
Description: The figure below shows several objects (A – D) of different masses located on the
surface of the earth.

A B C D
A. Ranking Instructions: Rank (from greatest to least) the strength of the gravitational force
exerted by Earth on each of the objects (A – D).
Ranking Order: Greatest 1 ______ 2 _______ 3 _______ 4 ______ Least
Or, the gravitational force exerted on each object is the same. _________ (indicate with a
check mark)
Carefully explain your reasoning for ranking this way:
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
B. Ranking Instructions: Rank (from greatest to least) the strength of the gravitational force
exerted by each object A – D on the Earth.
Ranking Order: Greatest 1 ______ 2 _______ 3 _______ 4 ______ Least
Or, the gravitational force exerted by each object is the same. _________ (indicate with a
check mark)
Carefully explain your reasoning for ranking this way:
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
Astronomy Ranking Task:
Gravity
Exercise #2

Description: The figures below (A – E) each show two rocky asteroids with masses (m),
expressed in arbitrary units, separated by a distance (d), also expressed in arbitrary units.

m = 20
D
d = 5
d = 5
d = 5
d = 5
d = 5
m = 5
m = 5
m = 3
m = 5
m = 3
m = 10 m = 10
B
E
C
D
m = 3
A

m = 10
A. Ranking Instructions: Rank (from greatest to least) the strength of the gravitational force
exerted on the asteroid located on the left side of each pair.
Ranking Order: Greatest 1 ____ 2 _____ 3 _____ 4 ____ 5 ____ Least
Or, the strength of the gravitational force exerted in each case is the same. _________
(indicate with a check mark)
Carefully explain your reasoning for ranking this way:
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
B. Ranking Instructions: Rank (from greatest to least) the strength of the gravitational force
exerted on the asteroid located on the right side of each pair.
Ranking Order: Greatest 1 ____ 2 _____ 3 _____ 4 ____ 5 ____ Least
Or, the strength of the gravitational force exerted in each case is the same. _________
(indicate with a check mark)
Carefully explain your reasoning for ranking this way:
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
Astronomy Ranking Task:
Gravity
Exercise #3
Description: In the picture below, the Earth-Moon system is shown (not to scale) along with five
possible positions (A – E) for a spacecraft traveling from Earth to the Moon. Note that position
C is exactly half-way between Earth and the Moon..
A. Ranking Instructions: Rank (from greatest to least) the strength of the gravitational force at
positions A – E exerted by the Moon on the spacecraft.
Ranking Order: Greatest 1 ______ 2 _______ 3 _______ 4 ______ 5 ______ Least
Or, the gravitational force exerted at each position is the same. _________ (indicate with a
check mark)
Carefully explain your reasoning for ranking this way:
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
B. Ranking Instructions: Rank (from greatest to least) the strength of the net (or total)
gravitational forces at positions A – E exerted by both the Earth and the Moon on the
spacecraft.
Ranking Order: Greatest 1 ______ 2 _______ 3 _______ 4 ______ 5 ______ Least
Or, the gravitational force exerted at each position is the same. _________ (indicate with a
check mark)
Carefully explain your reasoning for ranking this way:
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
D 
Earth
E 
A 
C 
Moon
B 
Astronomy Ranking Task:
Gravity
Exercise #6
Description: The table below shows the masses and distances (expressed in arbitrary units)
between four different pairs of stars (Cases A – D).
Case
Mass of star
#1
Distance between
star #1 and star #2 Mass of
star #2
A 4 2 2
B 2 2 8
C 8 4 4
D 1 3 5
Ranking Instructions: Rank (from greatest to least) the strength of the gravitational force
exerted between the pairs of stars in cases A – D.
Ranking Order: Greatest 1 ______ 2 _______ 3 _______ 4 ______ Least
Or, the strength of the gravitational force exerted between each pair of stars is the same.
_________ (indicate with a check mark)
Carefully explain your reasoning for ranking this way:
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________