by redmafiya » Fri Jul 11, 2008 11:39 pm
For a free falling object, the distance D covered in a given time interval (t, T) can be expressed as:
[tex]D = \frac{1}{ 2}g(T^2 - t^2)[/tex]
So we can set up a system of two equations based on the given information:
[tex]60 = \frac{1}{2}g(T^2 - t^2)[/tex] ......................(1)
[tex]T - t = 2[/tex] .....................................................(2)
Solving for T and t, we have
[tex]T = 1 +\frac{30}{g} = 4[/tex]
[tex]t = T - 2 = 2[/tex]
[tex]H = \frac{1}{2}gT^2 = \frac{1}{2}g4^2 = 80[/tex]
So
It take the body 4 seconds to fall 80 meters