During an ice skating performance, an initially motionless $83\mathrm{.}8-$kg clown throws a fake barbell away. The clown$$s ice skates allow her to recoil frictionlessly. If the clown recoils with a speed of $0\mathrm{.}600$ m$/$s and the barbell is thrown with a speed of $13\mathrm{.}9$ m$/$s$,$ what is the mass of the barbell? Give your answer in kg$.$