Phy 121
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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: ->->->->->->->->->->->-> : The initial velocity is 0m/s and the final velocity has to be 3.125 m/s. Thus the acceleration has to be 3.125m/s divided by .64sec which gives us 4.88m/s^2.
3.125 m/s is average velocity; acceleration is not average velocity / change in clock time
• 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: ->->->->->->->->->->->-> : The initial velocity will be 0m/s and the final velocity will be 4.76m/s. Thus, the acceleration has to be 4.76m/s divided by 1.05s which gives us 4.53m/s^2. This is somewhat consistent with the previous problem.
• Are these observations consistent with the accepted value of the acceleration of gravity, which is 9.8 m / s^2?
answer/question/discussion: ->->->->->->->->->->->-> : They are not very consistent with this acceleration.
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20 minutes
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Solution
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