Question 1007759
Assuming there is no air resistance and gravity {{{g}}} is equal to {{{32.2}}}{{{(ft)/s^2}}}
{{{v=int(a,dt)=-gt+c[1]}}}
When {{{t=0}}}, {{{v=0}}}.
{{{c[1]=0}}}
{{{v=-gt}}}
So then,
{{{d=int(v,dt)=-(g/2)t^2+c[2]}}}
When {{{t=0}}}, {{{d=400}}}
{{{c[2]=400}}}
{{{d=-16.1t^2+400}}}
Find {{{t}}} when the stone hits the ground {{{d=0}}},
{{{16.1t^2=400}}}
{{{t^2=400/16.1}}}
{{{t=4.98}}}
So then the velocity is,
{{{v=-32.2(4.98)}}}
{{{v=-160.5}}}{{{fps}}}