A.2 - 5 - Static v Kinetic Friction

What is the nature of friction as a force?

• It acts in the same direction as an object's motion.

• It acts perpendicular to the surface and against an object's motion.

• It acts parallel to the surface and against an object's motion.

• It is independent of the surface an object is on.

Which factors primarily determine the magnitude of the force of friction?

• The object's velocity and acceleration.

• The normal force acting on the object and the materials of the surfaces in contact.

• The object's mass and volume.

• The temperature of the surfaces and the object's shape.

What is a key characteristic of the coefficient of friction (μ)?

• It is always a negative value.

• It has units of Newtons.

• It is a dimensionless quantity.

• It is always greater than 1.

How does the coefficient of static friction (μs) compare to the coefficient of kinetic friction (μk) for any given surface?

• μs is always less than μk.

• μs is always equal to μk.

• μs is always greater than μk.

• The relationship varies depending on the specific materials.