SOLUTION: A model rocket is launched with an initial upward velocity of 50 m/s. The rockets height “h@ (in meters) after “t” seconds is given by the following. H=50t-5t squared Fin

Algebra ->  Rate-of-work-word-problems -> SOLUTION: A model rocket is launched with an initial upward velocity of 50 m/s. The rockets height “h@ (in meters) after “t” seconds is given by the following. H=50t-5t squared Fin      Log On


   



Question 1145770: A model rocket is launched with an initial upward velocity of 50 m/s. The rockets height “h@ (in meters) after “t” seconds is given by the following.
H=50t-5t squared
Find all values of “t” for which the Rockets height is 20 meters
Round your answer to the nearest hundredth

Answer by ikleyn(52814) About Me  (Show Source):
You can put this solution on YOUR website!
.
These values of t are the roots of the equation


    H(t) = 20,  which is  -5t^2 + 50t = 20.


Write it in the standard form


    5t^2 - 50t + 20 = 0.


Solve it using the quadratic formula.


The two roots will be your answers.


The problem has two answers: one for for the model moving up and another for the model falling down.

Having my instructions, you do the rest.

If you still have questions or problems with it, then let me know.



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Comment from student: Thank u. I got 0.42 and 9.58. Is that correct ?
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My response :   YES  (!)  It is  CORRECT  (!)

Nice job !


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As my reward and a bonus to you for your nice job, here is the list of my lessons in this site related to similar problems

    - Problem on a projectile moving vertically up and down
    - Problem on an arrow shot vertically upward
    - Problem on a ball thrown vertically up from the top of a tower
    - Problem on a toy rocket launched vertically up from a tall platform

Consider these lessons as your textbook,  handbook,  tutorials and  (free of charge)  home teacher.
Read them attentively and learn how to solve this type of problems once and for all.

Also,  you have this free of charge online textbook in ALGEBRA-I in this site
    - ALGEBRA-I - YOUR ONLINE TEXTBOOK.

The referred lessons are the part of this textbook under the topic "Projectiles launched/thrown and moving vertically up and dawn".


Save the link to this online textbook together with its description

Free of charge online textbook in ALGEBRA-I
https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson

to your archive and use it when it is needed.