"What is the work doen by friction on a 15 kg object pulled horizontally in a straigth line for 15 meters, if the coefficient of friction between the object and the surface is given by uk = .04?" a) -59 J b) -91 J c) -145 J d) -590 J e) -890 J Im not sure how I would solve this problem. From what I've read, and was given, "the work done on an object is equal to the product of the parallel component of force and the magnitude of displacement it causes." well, the displacement was 15m, but the component of the force is what im having trouble with. The normal force is 147, multiplied by .04 would give me 58.8. This would lead me to choice A, however, Im sure im missing some important steps.