cq_1_071

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PHY121

Your 'cq_1_07.1' 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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A ball falls freely from rest at a height of 2 meters. Observations indicate that the ball

reaches the ground in .64 seconds.

Based on this information what is its acceleration?

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

2m/0.64sec = 3.125m/s

a=3.125m/sec/0.64sec = 4.882m/sec^2

@& Acceleration is based on change in velocity, not aveage velocity.*@

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Is this consistent with an observation which concludes that a ball dropped from a height of

5 meters reaches the ground in 1.05 seconds?

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

5m/1.05se=4.762m/sec

a=(4.762m/sec)/1.05sec = 4.535m/sec^2

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Are these observations consistent with the accepted value of the acceleration of gravity,

which is 9.8 m / s^2?

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

No, these figures are significantly lower than the accepted value, assuming they are correct.

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10 minutes

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Are my calculation correct? If not, what did I do wrong?

@& See my note. You used average velocity where you should have used the change in velocity.

&#Please see my notes and, unless my notes indicate that revision is optional, submit a copy of this document with revisions and/or questions, and mark your insertions with &&&& (please mark each insertion at the beginning and at the end).

Be sure to include the entire document, including my notes.

If my notes indicate that revision is optional, use your own judgement as to whether a revision will benefit you.

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