If a 11 kg11kg object moving at 45 m/s45ms slows down to a halt after moving 900 m900m, what is the coefficient of kinetic friction of the surface that the object was moving over?
By conservation of mechanical energy Work done against Frictional force = KE of the object mu_kxxmxxgxxd=1/2xxmv^2μk×m×g×d=12×mv2 mu_k=v^2/(2gd)=45^2/(2xx10xx900)=0.1125μk=v22gd=4522×10×900=0.1125