This is mostly a theoretical question, I'm studying mechanics by myself so I have no teacher to ask this. 1. The problem statement, all variables and given/known data The minimum force needed to move a stationary object is equal to the max static friction. However, I just encountered a question that included a sloped surface and an object moving upwards across it. Eventually, mgcos(a)+Fk bring it to a halt, and the question is what should the minimal static friction constant be in order for the object to remain stationary. 3. The attempt at a solution Fs must be strong enough to hold out against mgcos(a). The equation we are supposed to have is Fs-mgcos(a)=0 However, this confuses me. If when a force applied on the object equals to Fs(max) it causes it to move, Shouldn't the force needed to keep the object from moving be Fs>mgcos(a)? In other words, is Fs(max) the breaking point or the last point before movement occurs?