Question

A rocket is launched at t = 0 seconds. Its height, in meters above sea-level, is given by the equation

h = -4.9t2 + 112t + 395.
At what time does the rocket hit the ground? The rocket hits the ground after how many seconds

Answer 1

Explanation:

In order to find out how long it takes for the rocket to hit the ground, we only need set that position equation equal to 0 (that's how high something is off the ground when it is sitting ON the ground) and factor to solve for t:

`0=-4.9t^2+112t+395`

Factor that however you are factoring in class to get

t = -3.1 seconds and t = 25.9 seconds.

Since time can NEVER be negative, it takes the rocket approximately 26 seconds to hit the ground.