(Y2:2) Forces and friction

For an inclined plane resolve the forces to what parallel

The slope parallel is most often a lot easier then the true parallel (The ground / horizontal)

How to find the maximum or limiting value of friction

F_max = µR (µ is the coefficient of friction for that surface pair and R is the normal reaction between the two surfaces)

When is the friction force at it max

When it is on the limit of equilibrium and so motion is about to occur if any more force is applied

Often the exams will use phrases like “about to slip“ or “on the point of moving“

direction of friction

It opposes motion and so is the opposing direction to the resultant force moving it and parallel to the surface the object is on