what's the formula of?

Question

when you fell an object from a 10th floor bldg,you can get the height of that bldg. by counting how many seconds until you hear that objects sound.can you give me the formula and the solution of it?thanks a lot

Answer 1

Let the height of the building be "d", let "a" be the acceleration due to gravity, which is -9.8 m/s^2 or -32 ft.s^2. Let "t" be time.

d = (1/2)*a*t^2, if you want the distance.

Algebraic rearrangement gives:

t = (plus or minus) sqrt(2d/a) if you want the time.

The positive root should be the answer. Make sure the units for d and a cancel appropriately (i.e., you should end up with seconds).

Answer 2

a = -32ft/sec^2
v = -32t +c = -32t since c=0
h = -16t^2 +c = -16t^2+ho
So ho = 16t^2 since h = 0 when object strikes ground

So if it takes 3 seconds the height is 16*3^2 = 144 feet.

The number of stories has nothing to do with the problem.

Answer 3

First of all what r u looking for, specifically, because there r alot of formulas for, speed, velocity, acceleration, etc.