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Cengage - Interactive Video Vignettes 1/e (Homework)

James Finch

Physics - College, section 1, Fall 2019

Instructor: Dr. Friendly

Current Score : 8 / 8

Due : Monday, January 28, 2030 00:00 EST

Last Saved : n/a Saving...  ()

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Question
Points
1 2
3/3 5/5
Total
8/8 (100.0%)

  • Instructions

    Interactive Video Vignettes (IVVs) are video-based online tutorials developed by Cengage through research funded by the National Science Foundation. In each IVV, students watch video of real students exploring concepts and conducting experiments, perform online video analysis, and answer questions that help address learning difficulties identified by PER (Physics Education Research). The sample assignment below includes two from the collection of 37 IVVs. This demo assignment allows many submissions and allows you to try another version of the same question for practice wherever the problem has randomized values.

Assignment Submission

For this assignment, you submit answers by question parts. The number of submissions remaining for each question part only changes if you submit or change the answer.

Assignment Scoring

Your last submission is used for your score.

1. 3/3 points  |  Previous Answers CenIVV1 1.5.001. My Notes
Question Part
Points
Submissions Used
1 2 3
1/1 1/1 1/1
2/100 2/100 3/100
Total
3/3
 
Watch the video vignette below, and be sure to follow any instructions when prompted during the videos. Then answer the questions below about the concepts discussed in the video.
(a)
Block A with a mass of 1 kg and block B with a mass of 2 kg lie on a smooth table. You wish to apply a horizontal force to each ball to give them the same horizontal acceleration (and you may safely ignore friction). Which of the following best describes the relative magnitude of the forces you must apply?
     Correct: Your answer is correct.
(b)
Block A has a mass of 1 kg and block B has a mass of 2 kg. Which of following best describes the relative magnitudes of the gravitational force (due to the Earth) on each block?
     Correct: Your answer is correct.
(c)
You hold block A with a mass of 1 kg in one hand and block B with a mass of 2 kg in the other. You release them both from the same height above the ground at the same time. (Air resistance can safely be ignored as they fall.) Which of the following describes and explains the motion of the two objects after you release them?
     Correct: Your answer is correct.


Solution or Explanation
(a)
The larger mass object has more inertia, which means it is "harder" to get it to move in the same way as the lighter object. According to Newton's second law, an object's acceleration is proportional to the force applied to it but inversely proportional to the object's mass. Therefore, twice as much force is needed on block B, which has twice as much mass as block A, for them to accelerate in the same way.
(b)
The gravitational force on the object is proportional to the mass of the object. So the gravitational force on block B is twice as much as the gravitational force on block A, because block B has twice the mass.
(c)
As demonstrated in the video, the two objects will hit the ground at the same time. Despite their different masses, and despite the fact that the gravitational force on them is different, their accelerations will be the same. While the greater gravitational force on the more massive object would tend to increase its acceleration, its greater mass also tends to make it more difficult to accelerate. These two effects turn out to exactly compensate for each other.
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2. 5/5 points  |  Previous Answers CenIVV1 4.4.001. My Notes
Question Part
Points
Submissions Used
1 2 3 4 5
1/1 1/1 1/1 1/1 1/1
1/100 1/100 2/100 1/100 1/100
Total
5/5
 
Watch the video vignette below, and be sure to follow any instructions when prompted during the videos. Then answer the questions below about the concepts discussed in the video.
(a)
In the video above, a charged metal sphere on a prod touched a hanging metal sphere. Which of the following best describes the magnitude of charge on each sphere after touching?
     Correct: Your answer is correct.
(b)
Which of the following best describes the relative signs of charge on each sphere after touching?
     Correct: Your answer is correct.
(c)
Which of the following best describes what happened to the hanging sphere after touching, and why?
     Correct: Your answer is correct.
(d)
A charged prod, such as the one seen in the video, is brought near an identical charged hanging sphere. Consider the dependence of the electric force on distance that you found in the video. Based on this, what would happen to the force on the hanging sphere if the distance between the spheres was doubled?
     Correct: Your answer is correct.
(e)
What is the magnitude of the electric force on a +2.00 nC charged particle due to a +3.00 nC charged particle that is 4.00 cm away from it? Use the equation for the force between two charged objects discussed in the video.
    
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