cq_1_041

Phy 121

Your 'cq_1_04.1' 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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The problem:

A ball is moving at 10 cm/s when clock time is 4 seconds, and at 40 cm/s when clock time is 9 seconds.

Sketch a v vs. t graph and represent these two events by the points (4 sec, 10 cm/s) and (9 s, 40 cm/s).

answer/question/discussion: ->->->->->->->->->->->-> :

I plotted (4 sec, 10 cm/s) and (9s, 40 cm/s) on a graph.

Sketch a straight line segment between these points.

answer/question/discussion: ->->->->->->->->->->->-> :

I sketched a straight line segment between these points.

What are the rise, run and slope of this segment?

answer/question/discussion: ->->->->->->->->->->->-> :

Rise = y2 - y1 = 40 cm/s - 10 cm/s = 30 cm/s

Run = x2 - x1 = 9 s - 4 s = 5 s

Slope = rise / run = 30 cm/s / 5 s = 6 cm / s^2 or 6

What is the area of the graph beneath this segment?

answer/question/discussion: ->->->->->->->->->->->-> :

Area of triangle = 1/2 b h or 1/2*run*rise = 1/2*5*30 = 75 (units?)

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15 minutes

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Very good, but for calculation of area it's a trapezoid rather than a triangle. See the link below (no revision required; you'll understand... but of course submit a revision if you don't).

&#Please compare your solutions with the expanded discussion at the link

Solution

Self-critique your solutions, if this is necessary, according to the usual criteria. Insert any revisions, questions, etc. into a copy of this posted document. Mark any insertions with &&&& so they can be easily identified. &#