Posted by **guy** on Thursday, October 28, 2010 at 10:46am.

On Earth a rock falls an unknown vertical distance from a resting position and lands in a lake. If it takes the rock 2.5 seconds to fall, how high is the cliff that the rock fell from?

- physics -
**jai**, Thursday, October 28, 2010 at 11:00am
the formula for vertical distance is,

d = (v0)*t-(1/2)g*t^2

where v0=initial velocity, t=time, and g=acceleration due to gravity, which is approximately 9.8 m/(s^2)

*now since this is freefall, v0 = 0 and the formula reduces to:

d = -(1/2)g*t^2

d = -(1/2)*9.8*(2.5^2)

then solve for d. units in m. (get its absolute value since it's distance)

- physics -
**guy**, Tuesday, November 2, 2010 at 1:22pm
THANK YOU =0]

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