The 5-kg skate board rolls down the 5° slope at constant speed. If the coefficient of kine...

The 5-kg skate board rolls down the 5° slope at constant speed. If the coefficient of kinetic friction between the 12.5-mm-diameter axles and the wheels is µk = 0.3, determine the radius of the wheels. Neglect rolling resistance of the wheels on the surface. The center of mass for the skateboard is at G.