Question 331551
from the looks of it u have an equation
{{{y=.9t^2}}}
and you have what y =
{{{y<4}}}
so:
{{{4>.9t^2}}}divide by .9
{{{4.4444>t^2}}}
t=2.1082 or -2.1082 since we cant go back in time negative wouldnt be an answer
so the time takes less than 2.1082 seconds
range from [0 ,  2.1082]