Question 959302
{{{ h = -16t^2 + v*t + c }}}
-------------------------
change {{{ h }}} to {{{ h(t) }}} 
( helps to explain better )
{{{ h(t) = -16t^2 + v*t + c }}}
----------------------------
The height is {{{ 5 }}} ft when the
cannon is fired at {{{ t=0 }}}, so
{{{ h(0) = 5 }}}
{{{ 5 = -16*0^2 + v*0 + c }}}
{{{ 5 = c }}}
-----------------------------
You are given:
{{{ h(3) = 131 }}}
{{{ h(3) = -16*3^2 + v*3 + 5 }}}
{{{ 131 = -16*3^2 + v*3 + 5 }}}
{{{ 3v = 131 + 16*9 - 5 }}}
{{{ 3v = 131 + 144 - 5 }}}
{{{ 3v = 275 - 5 }}}
{{{ 3v = 270 }}}
{{{ v = 90 }}}
The initial velocity is 90 ft/sec
----------------------------
When {{{ t=0 }}}
{{{ h(0) = -16*0^2 + v*0 + 5 }}}
{{{ h(0) = 5 }}}
What ever the velocity is at {{{ t=0 }}}
the height is still {{{ 5 }}} ft, so
the velocity can't be determined 
from this equation