Material/Object characteristics	Mass (kg)	Normal Force (N)	Force of Static Friction (N)	Force of Kinetic Friction (N)	Coefficient of Kinetic Friction (rounded to two decimal places)	Coefficient of Static Friction (rounded to two decimal places)
One Concrete Block -large side down	0.50		3.1	1.9
One Concrete Block -small side down	0.50		3.1	1.9
Two ConcreteBlocks Stacked	1.0		6.2	3.9
One Block of same mass but different material (Steel)	0.50		2.1	1.7

Diagrams: Draw free body diagrams to show the forces acting on one concrete block for the following scenarios:

1. Not moving and not being pulled by the spring.
2. Not moving and being pulled by the spring and static friction was at its maximum.
3. Accelerating and being pulled by a force larger than the force required to move it in uniform motion.
4. Being pulled by a sufficient force to maintain uniform motion.

All forces require labels and appropriate values in Newtons.

Analysis:

1. How did the forces of kinetic friction compare for the block with the large side down versus the small side down? How did the forces of static friction compare? What can you conclude about the effect of surface area on friction?

1. How did the forces of kinetic friction compare for one block versus two stacked blocks? How did the forces of static friction compare? What can you conclude about the effect of mass on friction?

1. How did the forces of static friction compare for the two blocks of identical masses but different materials? How did the forces of kinetic friction compare? What can you conclude about the effect of materials in contact on force of friction?

1. How did the coefficients of static friction compare in all cases? How did the coefficients of kinetic friction compare? According to this, on what do coefficients of friction depend?

1. How do the coefficients of static and coefficient compare with each other and forces of static and kinetic friction compare with each other?