Revised Seed 71

course PHY 121

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?

2m / .64s = 3.1m/s

####This should be 3.1m/s * 2 = 6.2m/s

####6.2m/s / 0.64s = 9.7m/s^2

answer/question/discussion:

• 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?

No because 5m / 1.05s = 4.8m/s

####This is 2 * 4.8m/s = 9.6m/s

###9.6m/s / 1.05s = 9.1m/s^2

answer/question/discussion:

• Are these observations consistent with the accepted value of the acceleration of gravity, which is 9.8 m / s^2?

no

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