Question 1143950
{{{ d/16 = t^2 }}}
{{{ d }}} is in ft and 
{{{ t }}} is in sec
Given:
{{{ d = 64 }}}
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{{{ 64/16 = t^2 }}}
{{{ 4 = t^2 }}}
Take the square root of both sides
{{{ 2 = t }}}
It takes 2 sec to fall 64 ft