A $12-$pack of Coca$-$Cola $($ is initially at rest on a horizontal floor. It is then pushed in a straight line

for $1\mathrm{.}20$ m by a trained dog that exerts a horizontal force with magnitude $36\mathrm{.}0$ N$.$ Use work$-$energy

theorem to find the final speed of the $12-$pack if $($a$)$ there is no friction between the $12-$pack and the

floor, and $($b$)$ the coefficient of kinetic friction between the $12-$pack and the floor is $0\mathrm{.}3.($Young$,$

$6\mathrm{.}27)$