cq_1_022

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Phy 121

Your 'cq_1_02.2' 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_02.2_labelMessages **

The problem:

A graph is constructed representing velocity vs. clock time for the interval between clock times t = 5 seconds and t = 13 seconds. The graph

consists of a straight line from the point (5 sec, 16 cm/s) to the point (13 sec, 40 cm/s).

What is the clock time at the midpoint of this interval?

answer/question/discussion: ->->->->->->->->->->->-> scussion (start in the next line):

'dt2+'dt1=13+5=18

18/2=9

9 sec is midpoint clock time

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What is the velocity at the midpoint of this interval?

answer/question/discussion: ->->->->->->->->->->->-> scussion (start in the next line):

v2+v1=16+40=56

56/2=28

28 cm/s is midpoint velocity

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How far do you think the object travels during this interval?

answer/question/discussion: ->->->->->->->->->->->-> scussion (start in the next line):

'ds= vave* 'dt

'ds=28*8=224cm

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By how much does the clock time change during this interval?

answer/question/discussion: ->->->->->->->->->->->-> scussion (start in the next line):

'dt= 'dt2-'dt1 =13-5=8 seconds

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By how much does velocity change during this interval?

answer/question/discussion: ->->->->->->->->->->->-> scussion (start in the next line):

'vave= vave2-vave1= 40-16= 24 cm/s

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What is the average rate of change of velocity with respect to clock time on this interval?

answer/question/discussion: ->->->->->->->->->->->-> scussion (start in the next line):

aveage rate of change of velocity= 'vave/'dt

=(24cm/s)/(8 sec)

=3 cm/s^2

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What is the rise of the graph between these points?

answer/question/discussion: ->->->->->->->->->->->-> scussion (start in the next line):

rise = 'vave

=24 cm/s

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What is the run of the graph between these points?

answer/question/discussion: ->->->->->->->->->->->-> scussion (start in the next line):

run= 'dt

=8sec

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What is the slope of the graph between these points?

answer/question/discussion: ->->->->->->->->->->->-> scussion (start in the next line):

slope = rise/ run = aveage rate of change of velocity

slope= 24

=3 cm/s^2

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What does the slope of the graph tell you about the motion of the object during this interval?

answer/question/discussion: ->->->->->->->->->->->-> scussion (start in the next line):

the motion of the object is increasing at a constant rate.

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What is the average rate of change of the object's velocity with respect to clock time during this interval?

answer/question/discussion: ->->->->->->->->->->->-> scussion (start in the next line):

aveage rate of change of velocity= 'vave/'dt

=(24cm/s)/(8 sec)

=3 cm/s^2

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*#&!*#&!

@&

Your units were pretty good here; you might have missed the final units on one question but got them on most.

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