$4.$ A $1\mathrm{.}0-$kg wheel in the form of a solid disk rolls along a horizontal surface with a speed of $6\mathrm{.}0$ m$/$s$.$ What is the total kinetic energy of the wheel?

a$)$ What was the angular acceleration $($in rad$/$s$2)$ of the grinding wheel as it came to rest if we take a counterclockwise rotation as positive?

b$)$ How many revolutions did the wheel make during the time it was coming to rest?