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Ch4 HW4 f10 (Homework)
Ashlyn Baum
Physics 303K, section B, Fall 2010
Instructor: Jim Chelikowsky
Current Score :
23 / 29
Due :
Thursday, September 30, 2010 11:30 PM CDT
1.
1.5/1.5 points
Question: MI3 4.10.X.011
2.
4/4 points
Question: MI3 4.10.X.012
3.
2.5/2.5 points
Question: MI3 4.11.X.072
A ball whose mass is
1.8
kg is suspended from a spring whose stiffness is
5
N/m. The ball
oscillates up and down with an amplitude of
14
cm.
The due date for this assignment is past.
Your work can be viewed below, but no changes can be made.
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If an object is moving with constant momentum
‹
11
,
−
14
,
−
5
›
kg · m/s, what is the rate of
change of momentum
d
/
dt
?
d
/
dt
=
(kg · m/s)/s
What is the net force acting on the object?
net
=
N
The velocity of a ball changes from
‹
7
,
−
4
, 0
›
m/s to
‹
6.92
,
−
4.32
, 0
›
m/s in
0.04
s, due
to the gravitational attraction of the Earth and to air resistance. The mass of the ball is
140
grams.
(a) What is the acceleration of the ball?
=
2
, 8
, 0
(m/s)/s
(b) What is the rate of change of momentum of the ball?
d
/
dt
=
0.28
, 1.12
, 0
(kg · m/s)/s
(c) What is the net force acting on the ball?
net
=
0.28
, 1.12
, 0
N
Page 1 of 5
Ch4 HW4 f10
11/21/2010
http://www.webassign.net/v4cgiashlyn@utexas/student.pl?k=20101121222654ashlyn@ut.
..
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View Full Document(a) What is the angular frequency?
= 1.667
radians/s
(b) What is the frequency?
f
= 0.26525
hertz (cycles per second)
(c) What is the period?
T
= 3.769
s
(d) Suppose this apparatus were taken to the Moon, where the strength of the
gravitational field is only 1/6 of that on Earth. What would the period be on the Moon?
(Consider carefully how the period depends on properties of the system; look at the
equation.)
T
= 3.769
s
4.
3/3 points
Question: MI3 4.11.X.073
A mass of
2.9
kg is connected to a horizontal spring whose stiffness is
6.5
N/m. When the
spring is relaxed,
x
= 0. The spring is stretched so that the initial value of
x
= +
0.18
m. The
mass is released from rest at time
t
= 0. Remember that when the argument of a
trigonometric function is in radians, on a calculator you have to switch the calculator to radians
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 Fall '10
 Chelikowsky

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