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Phy121
Your 'cq_1_06.1' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
** CQ_1_06.1_labelMessages **
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, vf, `ds are given in this problem. v0 = 10 cm/s, vf = 20 cm/s, and `ds = 45 cm (I am not sure if the instructor wants us to solve the remaining 2 quantities or not).
`ds = (vf + v0) / 2 * `dt
`dt = `ds / [(vf + v0) /2] = 45 cm / [(20 cm/s + 10 cm/s) / 2] = 45 cm / (30 cm/s / 2) = 45 cm / 15 cm/s = 3 s
vf = v0 + a `dt
a = (vf - v0) / `dt = (20 cm/s - 10 cm/s) / 3 s = 10 cm/s / 3 s = 3.3 cm/s^2
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•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: ->->->->->->->->->->->-> :
We are given a, `dt, and vf. a = 10 cm/s^2, `dt = 3 s, and vf = 50 cm/s
vf = v0 + a `dt
v0 = vf - a `dt = 50 cm/s - 10 cm/s^2 * 3s = 50 cm/s - 30 cm/s = 20 cm/s
`ds = (vf + v0) / 2 * `dt = (50 cm/s + 20 cm/s) / 2 * 3 s = 70 cm/s / 2 * 3 s = 35 cm/s * 3 s = 105 cm
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•A ball travels 30 cm along an incline, starting from rest, while accelerating at 20 cm/s^2.
answer/question/discussion: ->->->->->->->->->->->-> :
In this problem we are given `ds, v0, and a. `ds = 30 cm, v0 = 0 cm/s, and a = 20 cm/s^2
vf^2 = v0^2 + 2 a `ds = (0 cm/s)^2 + 2 * 20 cm/s^2 * 30 cm = 1200 cm^2/s^2
vf = square root (1200 cm^2/s^2) = 34.6 cm/s
vf = v0 + a `dt
`dt = (vf - v0) / a = (34.6 cm/s - 0 cm/s) / 20 cm/s^2 = 34.6 cm/s / 20 cm/s^2 = 1.73 s
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Then for each situation answer the following:
•Is it possible from this information to directly determine vAve?
answer/question/discussion: ->->->->->->->->->->->-> :
Yes, I do believe it is possible.
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•Is it possible to directly determine `dv?
answer/question/discussion: ->->->->->->->->->->->-> :
Yes, I do believe it is possible to do so.
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&#Very good data and responses. Let me know if you have questions. &#