Question 1028179
What is the height when {{{ t = 0 }}} ?
That is the instant when the bolt is dropped?
{{{ h(0) = -16*0^2 + h }}}
{{{ h(0) = h }}}
You are told that this height is {{{ 120 }}} ft above ground
{{{ h(0) = 120 }}}
{{{ h = 120 }}}
So, now the equation is:
{{{ h(t) = -16t^2 + 120 }}}
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Now you want to find {{{ t }}} when {{{ h(t) = 0 }}}
{{{ 0 = -16t^2 + 120 }}}
{{{ 16t^2 = 120 }}}
{{{ t^2 = 15/2 }}}
{{{ t = sqrt( 7.5 ) }}}
{{{ t = 2.7386 }}}
The bolt takes 2.7386 sec to reach the ground