MATH
posted by ROBIN .
A frustrated office worker throws his laptop out of his business’s highrise
office building. The height, h, in meters of the laptop above the ground at t
seconds can be modelled by 2 h(t) 125 5t .
Estimate the instantaneous rate at which the laptop hits the ground.

sorry the equation is h(t)=125=1255t^2

h(t) = 125  5t^2
Take the derivative to find the velocity:
v(t) = dh(t)/dt = 10 t
Now:
Find the time when height is 0.
Find the velocity at that time. 
but when h is 0 t=0....

h = 1255t^2 = 0
5t^2 + 125 = 0
t^2  25 = 0
(t+5)(t5) = 0
t = 5
t = 5 s.
V = g*t = 9.8 * 5 = 49 m/s.