Problem $4$ According to Edmunds.com, the $2011$ Toyota Prius has a mass of $3042$ lbm$.$ If a Prius is

traveling at $40$ mph$,$ what is its kinetic energy, in kJ$?$ Assume that the Prius is brought to a stop and

of its kinetic energy is recovered and deposited in the battery pack, with the remaining being $60\%$

$,$lost to friction. If this same energy can then be extracted from the battery pack at $80\%$ efficiency

accelerating the vehicle, what will be its final speed, in mph$?($CLO $2\mathrm{.}1)$