Question

A frustrated office worker throws his laptop out of his business’s high-rise
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.

Answer 1

sorry the equation is h(t)=125=125-5t^2

Answer 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.

Answer 3

but when h is 0 t=0....

Answer 4

h = 125-5t^2 = 0
-5t^2 + 125 = 0
t^2 - 25 = 0
(t+5)(t-5) = 0

t = -5
t = 5 s.

V = g*t = 9.8 * 5 = 49 m/s.