Question

A falling object travels a distance given by the formula d=4t+16t^2, where t is measured in seconds and d is measured in feet how long will it take for the object to travel 72ft

Answer 1

2 seconds.

Explanation:

Given
`d=4t+16t^(2)` and d = 72 ft

We need to solve
`72=4t+16t^(2)`

`4t+16t^(2)-72=0`

`4t^(2)+t-18=0`

`4t^(2)+9t-8t-18=0`

`t(4t+9)-2(4t+9)=0`

`(t-2)(4t+9)=0`

`t-2=0,4t+9=0`

`t=2,t=-(9)/(4)`

Since, time can not be negative, so the required time is t = 2 seconds.