$($a$)$

Find the useful power output $($in W$)$ of an elevator motor that lifts a $2400$ kg load a height of $30\mathrm{.}0$ m in $12\mathrm{.}0$ s$,$ if it also increases the speed from rest to $4\mathrm{.}00$ m$/$s$.$ Note that the total mass of the counterbalanced system is $10,000$ kg$$so that only $2400$ kg is raised in height, but the full $10,000$ kg is accelerated. $($Enter a number.$)$

W

$($b$)$

What does it cost $($in cents$),$ if electricity is $$0\mathrm{.}0900$ per kW $$ h$?($Enter a number.$)$

cents