how do i calculate this?

[cheypie1000]

in physics we have to calculate a hang time for when people jump using their
average jump and i dont know how too.
He said to do something like this: =SQRT(2*average jump G4/9.8)*2
but everytime i use it, it doesnt work.
please help me
thanks

 

[Sheeloo]

Enter the (average) Jump height (in meters) in the cell A and paste this
formula in B1 to get the (average) hang time...
=2*SQRT(2*A1/9.8)

since g=9.8 m/s*s

 

[Shane Devenshire]

Hi,

In general a falling body starting from rest and accelerating under the
influence of gravity obeys the following formula:

S=1/2gt^2

distance = 1/2 * 9.8m/ss * (time)^2

where ^ means squared.

solving the above for t gives

t = (2*S*9.8)^2 or t = SQRT(2*S*9.8)

Of course I'm not sure how this has relevence to hang time, since I assume
that relates to falling through air, in which case air resistance becomes an
important factor even if no parachute is open. The above solution is for
free fall in a vacumn. For example, a free falling person in the atmosphere
reaches a terminal velocity because of air resistance, while the above
formula assumes no such factor.