Question

EXAMS NEXT WEEK! Help with Review! Giving Points!

The height of a javelin in feet is modeled by h(t)=-16t^2+79t+5, where t is the time in seconds after the javelin is thrown. Determine the maximum height of the javelin. After how many seconds does the javelin reach its maximum height? How many seconds does it take for the javelin to hit the ground?
1. Determine the maximum height of the javelin.
2. After how many seconds does the javelin reach its maximum height?
3. How many seconds does it take for the javelin to hit the ground?

Answer 1

rip english

Answer 2

im rewriting that

Answer 3

thats what i did and i got 79/32 or 2.46875

Answer 4

ok to find the x value in which you have your maximum y value use the equation -b/2a in which we pull the terms from the form of ax^2+bx+c

Answer 5

ok so you found 2.46 for your x value?

Answer 6

considering your x value is actually time i think at your maximum height would be the x value in which you found your maximum height. I seriously doubt they want us to use kinematics equations.

Answer 7

i think at your maximum height would be the x value in which you find the time it took to reach maximum height.

Answer 8

so what your saying is that 2.47 is my maximum height? if so then what would be the time?

Answer 9

yes i believe so