SOLUTION: This is from a worksheet from Glencoe Algebra 1. Mr Adim's science class launched a toy rocket from ground level with an initial upward velocity of 60 feet per second. The height

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Question 34797: This is from a worksheet from Glencoe Algebra 1.
Mr Adim's science class launched a toy rocket from ground level with an initial upward velocity of 60 feet per second. The height h of the rocket in feet above the ground after t seconds is modeled by the equation
.How long was the rocket in the air before it returned to the ground?
Found 2 solutions by longjonsilver, Earlsdon:
Answer by longjonsilver(2297) (Show Source):
You can put this solution on YOUR website!
the 60 feet per second is a red herring as such: it isn't used in the question by you.

The equation is one for height. Find the time taken to return to the ground. What height is the rocket when it finally returns to the ground? Answer that question and put that into the equation and then solve that equation to find the 2 values of t: one will be t=0, since at the start (t=0), the rocket was on the ground). The other answer, a positive value will be the time taken to return to the ground.

Have a go. :-)

jon.

Answer by Earlsdon(6294) (Show Source):
You can put this solution on YOUR website!
What you are really trying to ascertain is...when will the height of the rocket be at zero feet - again?
You can find this by setting the equation h (height) = 0 and solving for the time (t).
Factor out a t.
Apply the zero products principle.
and/or
When t = 0, the rocket has not yet stated its ascent.
Add 16t to both sides.
Divide both sides by 16.

The rocket returns to the ground after 3.75 seconds so it was in the air for 3.75 seconds.