+0

# The equation ​ describes the height (in feet) of a projectile launched from the ground at 80 feet per second. At what will the

0
52
4

The equation $$y = -16t^2 + 80t$$ describes the height (in feet) of a projectile launched from the ground at 80 feet per second. At what t will the projectile reach 36 feet in height for the first time? Express your answer as a decimal rounded to the nearest tenth.

Dec 2, 2020

#1
0

36    =  -16t^2 + 80 t

-16t^2 +80t -36 = 0        use quadratic formula to find values of  t

a = -16    b = 80   c = -36

$$x = {-b \pm \sqrt{b^2-4ac} \over 2a}$$                         the smaller 't' value will be the FIRST time it is at 36 ft

the other 't' value will be when it is on the way down

Dec 2, 2020
#2
0

Guest Dec 2, 2020
#3
0

CPHill help

Dec 2, 2020
#4
0

You obviously don't want 'help' ....you want someone to spoonfeed you the answers.....don't play on cphill's willingness to help !!!

Guest Dec 2, 2020