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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. &#