contestada

An object is dropped off a building that is 144 feet tall. After how many seconds does the object hit the ground? (s = 16t 2) 3 seconds 4 seconds 9 seconds

Respuesta :

3 seconds is the answer 

Answer:

t = 3 seconds

Step-by-step explanation:

Given that,

Height of the building, h = 144 feet

Initial speed of the object, u = 0

To find,

After how many seconds does the object hit the ground.

Solution,

The equation of an object when it falls from height h is given by :

[tex]h(t)=-16t^2+ut+h[/tex]

When the object hits the ground, h(t) = 0

[tex]-16t^2+144=0[/tex]

[tex]16t^2=144[/tex]

t = 3 seconds

So, the object will take 3 seconds to hits the ground.