Question 293018
The graph start at t=0, h=46 and go until h=0. 
{{{-16t^2+46=0}}}
{{{16t^2=46}}}
{{{t^2=23/8}}}
{{{t=1.696}}}
{{{ graph( 300, 300, 0, 2, -2, 48,  -16*x^2+46) }}}