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course PHY 241
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:
vf=?
v0=0
'dt=.64s
`ds=2m
a=?
`ds = (v0 + vf) / 2 * `dt
2m = (vf) / 2 * .64s
Vf=6.25m/s
6.25m/s = 0 + a * .64s
A=9.76m/s^2
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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:
vf=?
v0=0
'dt=1.05s
`ds=5m
a=?
`ds = (v0 + vf) / 2 * `dt
5m = (vf) / 2 * 1.05s
Vf=9.52m/s
vf = v0 + a * `dt
9.52m/s = 0 + a * 1.05s
A=9.07m/s^2
NO slightly different.
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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:
The first is consistent. The second is not.
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&#Good responses. Let me know if you have questions. &#