Question

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

Answer 1

3 seconds is the answer 

Answer 2

t = 3 seconds

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 :

`h(t)=-16t^2+ut+h`

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

`-16t^2+144=0`

`16t^2=144`

t = 3 seconds

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