During an ice skating performance, an initially motionless $88\mathrm{.}5-$kg clown throws a fake barbell away horizontally. The clown's ice skates allow her to recoil frictionlessly. Part $($a$)$ If the clown recoils with a speed of $0\mathrm{.}525$ m$/$s and the barbell is thrown with a speed of $9\mathrm{.}5$ m$/$s$,$ what is the mass, in kilograms, of the barbell?