If a toy rocket is launched vertically upward from ground level with an initial velocity of 135 feet per second, then its height h after t seconds is given by the equation h(t) = -16t2 + 135t. How long will it take the rocket to return to the ground? A-4.2 seconds
B-135 seconds
C-16 seconds
D-8.4 seconds

idk

step-by-step explanation:

46

step-by-step explanation:

given

height = 168 cm

formula

height =2.47*f+54.13

solution

168 = 2.47f + 54.13             subtract 54.13 from both sides

168 - 54.13   = 2.47f             combine

113.87 = 2.47f                     divide by 2.47

113.87 / 2.47 = f                   combine

46.1 = f  

answer: 46 cm