A 1.4 kg box slides 15m across the floor. The coefficient of kinetic friction between the box and the floor is 0.3. I found that friction force in slowing the box was -61.74J. Is this right? What was the initial velocity of the box? I worked this problem using Kf = Ki + Wnc and found that Vo =9.4m/s. Is this right? Also I would like to know how to work this problem another way with Energy. Any help with what formula to use or any help at all will be great.