Question 1198165
{{{H(t)=16t^2+80t }}}->trajectory is a paraola that opens down, so equation should be {{{H(t)=-16t^2+80t }}}

for the golf ball to hit the ground=>{{{H(t)=0}}}

{{{-16t^2+80t =0}}}

{{{-16t(t-5) =0}}}

{{{t=0}}}

or

{{{t=5}}}

the golf ball will hit the ground after {{{5}}} seconds