alexander (jra2623) – oldhomework 16 – Turner – (92510)
1
This
printout
should
have
9
questions.
Multiplechoice questions may continue on
the next column or page – find all choices
before answering.
001
10.0 points
The planet Mars has a mass of 6
.
1
×
10
23
kg
and radius of 3
.
4
×
10
6
m.
What
is
the
acceleration
of
an
object
in
free
fall
near
the
surface
of
Mars?
The value of the gravitational constant is
6
.
67259
×
10

11
N
·
m
2
/
kg
2
.
Correct answer: 3
.
521 m
/
s
2
.
Explanation:
Let :
M
= 6
.
1
×
10
23
kg
,
R
= 3
.
4
×
10
6
m
,
and
G
= 6
.
67259
×
10

11
N
·
m
2
/
kg
2
.
Near the surface of Mars, the gravitation
force on an object of mass
m
is
F
=
G
M m
R
2
,
so the acceleration of an object in free fall is
a
=
F
m
=
G
M
R
2
= (6
.
67259
×
10

11
N
·
m
2
/
kg
2
)
×
6
.
1
×
10
23
kg
(3
.
4
×
10
6
m)
2
=
3
.
521 m
/
s
2
.
002
10.0 points
An object has a weight
W
when it is on the
surface of a planet of radius
R
.
What will be the gravitational force on the
object after it has been moved to a distance
of 4
R
from the center of the planet?
1.
F
= 4
W
2.
F
= 16
W
3.
F
=
1
4
W
4.
F
=
1
16
W
correct
5.
F
=
W
Explanation:
On the surface of the planet,
W
=
G M m
R
2
.
When the object is moved to a distance 4
R
from the center of the planet, the gravitational
force on it will be
F
=
G M m
(4
R
)
2
=
G M m
16
R
2
=
1
16
G M m
R
2
=
1
16
W
.
003
10.0 points
Planet X has eight times the diameter and
five times the mass of the earth.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
This is the end of the preview.
Sign up
to
access the rest of the document.
 Summer '08
 Kaplunovsky
 Mass, Work, General Relativity, kg, Standard gravity

Click to edit the document details