Algebra: A Combined Approach (4th Edition)

Published by Pearson
ISBN 10: 0321726391
ISBN 13: 978-0-32172-639-1

Chapter 5 - Section 5.3 - Introduction to Polynomials - Exercise Set: 86

Answer

At $12.5$ seconds after launch.

Work Step by Step

We know that the polynomial $-16t^2+200t$ gives the height of the rocket at any time $t$. To find the moment at which the rocket hits the ground, we resolve for $t$ : $$-16t^2+200t=0$$ We have $t(-16t+200)=0$ by factorizing which means the rocket hits the ground for $t$ such that $-16t+200=0$. We get $200=16t$ and by dividing $t=200/16=12.5$ The answer is thus at $12.5$ seconds.
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.