An object is thrown upward at a speed of 171 feet per second by a machine from a height of 17 feet off the ground. the height h of the object after t seconds can be found using the equation h = − 16t^2 + 171t + 17 when will the height be 307 feet? when will the object reach the ground?

a.2.11 s or 8.57 s

b.10.79 s

Step-by-step explanation:

We are given that

Initial velocity=171 ft/s

Height  at which the object is thrown=17 ft

The height h of the object after t seconds can be found by the equation

a.We have to find  the time taken by object to reach the  height 307 ft.

Substitute the value

Quadratic formula :

Where

By using quadratic formula

Hence, the object will take 8.57 s or 2.11 s to reach the height 307 ft.

b.We have to find the time taken by object to reach the ground.

When the object reach the ground, then h=0

Substitute the value

Again by using quadratic formula

It is not possible because time cannot be negative.

Hence, the object will take 10.79 s to reach the ground.

b

step-by-step explanation: