The static frictional force is the force that opposes the relative movement between two objects when they are at rest one respect to the other. For example, it is the force that opposes when you try to push a furniture at your home while it does not start to move.
1.What
happens to the size of the static frictional force as you begin to pull
on the force scale?
As you begin to pull on the force scale the frictional force increases.
This is because the static frictional force opposes the force that you apply and while the object is not moving and you increase the force exerted by you the frictional force increases to give a net force of zero (again this is because the object is not moving => Net force = m*a = m * 0 = 0 => Force applied by you = static frictional force.
2.What happens to the stack of the books if the
applied force exceeds the maximum static frictional force?
In that moment, the stack of books starts to move.
3.What is the
minimum size for the static frictional force, and under what conditions
will the minimum static frictional force be observed?
The minimum size of the static frictional force is zero and in will be observed when there is not a pull or push force applied to the object.
4.What type of
friction acts when the books are at rest but a force is exerted?
The friction that acts when the books are at rest but a force is exerted is the static frictional force. On the other hand, the friction that acts when the books are moving is kynetic (dynamic) frictional force.
