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October 20, 2014

October 20, 2014

Posted by **Hayli** on Monday, February 20, 2012 at 10:22am.

a. How much time did it take the rock to hit the water?

b. What was its velocity when it was half of the distance to the water?

- Physics -
**drwls**, Monday, February 20, 2012 at 10:54amThe mass of the rock will not affect the answer.

a) Solve 3 = (g/2) t^2 to get t.

b) Solve 1.5 = (g/2) t^2 to get the time to fall half way,

t = sqrt(3/g)

and they use

V = g * t for the velocity V at that time, sqrt(3g). You can also use 3nergy conservation directly to get

the same answer.

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