cq_1_61

Phy 201

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 = 10 cm/s

vf = 20 cm/s

`ds = 10 cm/s

vAVE = (20 cm/s + 10 cm/s) / 2 = 30 cm/s

30 cm/s = 10 cm/s / `dt

3 s = `dt

`dt = 3 s

• 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: vf = 50 cm/s

aAVE = 10 cm/s^2

`dt = 3 s

aAVE = `ds / `dt

10 cm/s^2 = `ds / 3 s

3s * 10 cm/s^2 = `ds

30 cm/s = `ds

v0 = 20 cm/s

`ds = 30 cm/s

• A ball travels 30 cm along an incline, starting from rest, while accelerating at 20 cm/s^2.

answer/question/discussion:

v0 = 0 cm/s

vf = 60 cm/s

`dt = 3s

`ds = 60 cm/s

In this question I just played around with numbers until I got them to fit properly into formula for aAVE. I know there another way to do this kind of problem, but I don’t know how to use the quantity of 30 cm to come to a correct conclusion. How do I go about doing this?

Then for each situation answer the following:

• Is it possible from this information to directly determine vAve?

answer/question/discussion: I believe so, if you can determine aAVE then you can determine vAVE.

• Is it possible to directly determine `dv?

answer/question/discussion: Yes, as long as you can find initial and final velocity.

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15 minutes

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You're doing a good job here. See a fuller discussion in the link below; unless you have questions you can ignore the request 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. &#