1. The problem statement, all variables and given/known data This is not a specific problem, but is it true that if you added all of the forces acting on an object except for friction, that the direction of friction would be opposite the direction of that net force(technically, it's the net force except friction)? For example, If you knew that an object had the force of gravity, normal force, applied force and the force of friction acting on it, could you add the force of gravity, normal force, and applied force vectors and say that the direction of that sum is opposite the direction of friction? I know that friction is opposite the direction of motion, but I was just confused because I just did a question where you had to find the direction of the net force excluding friction in order to find the direction of the frictional force. 2. Relevant equations Fnet=sum of all forces. 3. The attempt at a solution I think that this statement is true, but I just want someone to confirm.