Phy 121
Your 'cq_1_6.1' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
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For each situation state which of the five quantities v0, vf, `ds, `dt and a are given, and give the value of each.
A ball accelerates uniformly from 10 cm/s to 20 cm/s while traveling 45 cm.
answer/question/discussion: ********* v0 = 10cm/s, vf = 20cm/s, `ds = 45cm
A ball accelerates uniformly at 10 cm/s^2 for 3 seconds, and at the end of this interval is moving at 50 cm/s.
answer/question/discussion: ********* ********* a = 10cm/s^2, `dt = 3s, vf = 50cm/s
A ball travels 30 cm along an incline, starting from rest, while accelerating at 20 cm/s^2.
answer/question/discussion: ********* ********* `ds = 30cm, v0 = 0, a = 20cm/s^2
Then for each situation answer the following:
Is it possible from this information to directly determine vAve?
answer/question/discussion: ********* ********* situation 1 yes vAve = 15cm/s, situation 2 yes vAve = 35cm/s, situation 3 yes vAve = 34.6cm/s
I don't believe vAve = 34.6 cm/s can be determined from the given information by direct reasoning, but I can show by direct reasoning that it's not quite correct. That result would imply a final velocity of 69.2 cm/s; accelerating at 20 cm/s^2 it would require over 3 seconds to achieve this velocity, and at an average of 34.6 cm/s the object would travel over 100 cm.
However you're close. If 34.6 cm/s is the final velocity then the average velocity is 17.3 cm/s, the time required to reah 34.6 cm/s would be about 1.73 seconds, and vAve * `dt would be 30 cm.
It still isn't likely that you obtained this result by direct reasoning, but you're doing goo work.
Is it possible to directly determine `dv?
answer/question/discussion: ********* ********* situation 1 yes `dv = 10cm/s, situation 2 yes `dv = 30cm/s, situation 3 no not directly from this information
Good.
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20 min
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See my notes, then see the document in the following link so you're sure you understand the meaning of 'direct reasoning', but unless there's something you don't understand, you can ignore the instruction to submit a revision.
&#At least part of your solution does not agree with the solution and comments given at the link below. You should view the solution at that link and self-critique as indicated there.
Solution
This link also expands on these topics and alerts you to many of the common errors made by students in the first part of this course. &#