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Quiz Feedback | Introductory Physics I with Laboratory
Feedback — Forces from Motion I
You submitted this quiz on Sat 22 Jun 2013 12:23 PM PDT (UTC -0700). You got a
score of 17.00 out of 24.00. You can attempt again, if you'd like.
Some questions provided by Matter and Interactions (3rd. Ed.), R. Chabay & B. Sherwood.
Copyright (2010, John Wiley & Sons). This material is used by permission of John Wiley &
Sons, Inc.
Question 1
For questions 1 to 3...
The figure above shows a moving ball, its momentum, and the net force acting on it an instant in
time. In the questions below,
component of
dp ⃗
dt
dp ⃗
dt
is rate of change of the ball's momentum,
that is parallel to the ball's momentum, and
dp ⃗
dt ⊥
dp ⃗
dt ∥
is the
is the component
perpendicular to the ball's momentum.
What is the direction of
dp ⃗
dt ∥
at this instant?
Your Answer
Score
Explanation
---select--a
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b

1.00
c
d
e
f
g
h
j
Total
1.00 / 1.00
Question Explanation
Answer : b
Question 2
What is the direction of
dp ⃗
dt ⊥
at this instant?
Your Answer
Score
Explanation
---select---
a
b
c
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c
d

1.00
e
f
g
h
j
Total
1.00 / 1.00
Question Explanation
Answer : d
Question 3
At this instant, the ball's speed is:
Your Answer
Score
Explanation
not changing
increasing

1.00
decreasing
Total
1.00 / 1.00
Question Explanation
Answer : increasing
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Question 4
For questions 4 to 6...
The figure above shows a moving ball, its momentum, and the net force acting on it an instant in
time. In the questions below,
component of
dp ⃗
dt
dp ⃗
dt
is rate of change of the ball's momentum,
that is parallel to the ball's momentum, and
dp ⃗
dt ⊥
dp ⃗
dt ∥
is the
is the component
perpendicular to the ball's momentum.
What is the direction of
dp ⃗
dt ∥
at this instant?
Your Answer
Score
Explanation
---select--a
b

0.00
c
d
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e
f
g
h
j
Total
0.00 / 1.00
Question Explanation
Answer : f
Question 5
What is the direction of
dp ⃗
dt ⊥
at this instant?
Your Answer
Score
Explanation
---select--a
b
c
d
e
f

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0.00
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g
h
j
Total
0.00 / 1.00
Question Explanation
Answer : d
Question 6
At this instant, the ball's speed is:
Your Answer
Score
Explanation
not changing
increasing
decreasing

Total
1.00
1.00 / 1.00
Question Explanation
Answer : decreasing
Question 7
For questions 7 to 9
A review of the basics of circular motion: The radius of a merry-go-round is 6 meters, and it
takes 13 seconds to go around once. We want to calculate the speed of an atom in the outer
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rim. First, how far does the atom go in 13 s? (This distance is the circumference of the circle.)
distance = ? m
You entered:
37.7
Your Answer
37.7
Score

Total
Explanation
1.00
1.00 / 1.00
Question Explanation
Answer : [35.82,39.59]
Question 8
Therefore, what is the speed of the atom?
speed = ? m/s
You entered:
2.9
Your Answer
2.9
Score

Total
Explanation
1.00
1.00 / 1.00
Question Explanation
Answer : [2.76,3.05]
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Question 9
What is the direction of the velocity of this atom?
Your Answer
Score
Explanation
tangential
towards the center
away from the center

Total
0.00
0.00 / 1.00
Question Explanation
Answer : tangential
v = (2π r)/T.
The velocity is tangential.
Question 10
For questions 10 to 24...
A comet orbits a star in an elliptical orbit, as shown. The momentum of the comet at location A is
also shown.
Use the directions shown to answer the following questions.
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At location A, what is the direction of the gravitational force exerted on the comet by the star?
Your Answer
Score
Explanation
---select--a
b
c
d
e
f
g

1.00
h
j
Total
1.00 / 1.00
Question Explanation
Answer : g
Question 11
At location A, is the parallel component of the net force on the comet zero or nonzero?
Your Answer
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Score
Explanation
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---select--zero
nonzero

Total
0.00
0.00 / 1.00
Question Explanation
Answer : zero
Question 12
At location A, is the perpendicular component of the net force on the comet zero or nonzero?
Your Answer
Score
Explanation
---select--zero
nonzero

Total
1.00
1.00 / 1.00
Question Explanation
Answer : nonzero
Question 13
At location A, is
⃗
d| p |
dt
, the rate of change of the magnitude of the comet's momentum, positive,
negative, or zero?
Your Answer
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Score
Explanation
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---select--positive

0.00
negative
zero
Total
0.00 / 1.00
Question Explanation
Answer : zero
Question 14
^, the direction of the comet's momentum, changing or not changing?
At location A, is p
Your Answer
Score
Explanation
---select--changing

1.00
not changing
Total
1.00 / 1.00
Question Explanation
Answer : changing
Question 15
At location B, what is the direction of the gravitational force exerted on the comet by the star?
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Your Answer
Score
Explanation
---select--a
b
c
d
e
f

1.00
g
h
j
Total
1.00 / 1.00
Question Explanation
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Answer : f
Question 16
At location B, is the parallel component of the net force on the comet zero or nonzero?
Your Answer
Score
Explanation
---select--zero
nonzero

Total
1.00
1.00 / 1.00
Question Explanation
Answer : nonzero
Question 17
At location B, is the perpendicular component of the net force on the comet zero or nonzero?
Your Answer
Score
Explanation
---select--zero
nonzero

Total
1.00
1.00 / 1.00
Question Explanation
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Answer : nonzero
Question 18
At location B, is
⃗
d| p |
dt
, the rate of change of the magnitude of the comet's momentum, positive,
negative, or zero?
Your Answer
Score
Explanation
---select--positive

1.00
negative
zero
Total
1.00 / 1.00
Question Explanation
Answer : positive
Question 19
^, the direction of the comet's momentum, changing or not changing?
At location B, is p
Your Answer
Score
Explanation
---select--changing
not changing

Total
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0.00
0.00 / 1.00
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Question Explanation
Answer : changing
Question 20
At location E, what is the direction of the gravitational force exerted on the comet by the star?
Your Answer
Score
Explanation
---select--a

1.00
b
c
d
e
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f
g
h
j
Total
1.00 / 1.00
Question Explanation
Answer : a
Question 21
At location E, is the parallel component of the net force on the comet zero or nonzero?
Your Answer
Score
Explanation
---select--zero
nonzero

Total
1.00
1.00 / 1.00
Question Explanation
Answer : nonzero
Question 22
At location E, is the perpendicular component of the net force on the comet zero or nonzero?
Your Answer
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Score
Explanation
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---select--zero
nonzero

Total
1.00
1.00 / 1.00
Question Explanation
Answer : nonzero
Question 23
At location E, is
⃗
d| p |
dt
, the rate of change of the magnitude of the comet's momentum, positive,
negative, or zero?
Your Answer
Score
Explanation
---select--positive

0.00
negative
zero
Total
0.00 / 1.00
Question Explanation
Answer : negative
Question 24
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^, the direction of the comet's momentum, changing or not changing?
At location E, is p
Your Answer
Score
Explanation
---select--changing

1.00
not changing
Total
1.00 / 1.00
Question Explanation
Answer : changing
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