Question

Please help.

Samantha threw an apple out of a window from the tenth floor of her apartment building. The equation y = -16t² +120 can be used to represent the fruit's height above the ground, where t represents time, in seconds, after she threw the apple. How long did it take the apple to hit the ground? Round your answer to the nearest hundredth.

The time must be in seconds.

Answer 1

2.74

Explanation:

Answer 2

we have

`y=-16t^(2) +120`

we know that

When the apple hit the ground the value of y is equal to zero

so

Find the x-intercept of the function

equate the function to zero

`-16t^(2) +120=0`

Group terms that contain the same variable, and move the constant to the opposite side of the equation

`-16t^(2) =-120`

`t^(2) =-120/-16`

`t^(2) =7.5`

`t=(+/-)√(7.5)`

`t=(+/-)2.74`

therefore

the answer is

`2.74\ sec`

using a graphing tool

see the attached figure to better understand the problem