.
As you know (or must know), the equation for the height above the ground for this case is
h(t) = -16t^2 + 56t.
The maximum height is reached when this quadratic function gets its maximum, i.e. at t = = = seconds,
and is equal to
= = 49 feet.
To find the zeroes, solve the equation
h(t) = 0, which is the same as -16t^2 + 56t = 0,
= 0,
so the zeroes are these values of t: t= 0 seconds (start) and t= = seconds (finish).
The problem was solved couple of days ago at this link
https://www.algebra.com/algebra/homework/Polynomials-and-rational-expressions/Polynomials-and-rational-expressions.faq.question.1115537.html
https://www.algebra.com/algebra/homework/Polynomials-and-rational-expressions/Polynomials-and-rational-expressions.faq.question.1115537.html
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For more details see the lessons
- 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
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.