What are the key differences between kinetic and static friction?

Kinetic Friction: Acts on moving surfaces, constant magnitude. | Static Friction: Acts on surfaces at rest, self-adjusting up to a maximum value.

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What are the key differences between kinetic and static friction?

Kinetic Friction: Acts on moving surfaces, constant magnitude. | Static Friction: Acts on surfaces at rest, self-adjusting up to a maximum value.

Compare the coefficients of static and kinetic friction.

Coefficient of Static Friction ( $\mu_s$ ): Usually greater than $\mu_k$ , represents the force needed to start motion. | Coefficient of Kinetic Friction ( $\mu_k$ ): Usually smaller than $\mu_s$ , represents the force needed to maintain motion.

Compare the forces involved when an object is at rest versus sliding down an inclined plane.

At Rest: Static friction balances the component of gravity pulling the object down the plane. | Sliding: Kinetic friction opposes the motion down the plane, but the net force results in acceleration.

What is the difference between the formulas for kinetic friction and maximum static friction?

Kinetic Friction: $F_k = \mu_k N$ (always equal to this value when sliding) | Maximum Static Friction: $f_{s,max} = \mu_s N$ (static friction can be any value from zero up to $f_{s,max}$ )

Compare the effect of contact area on kinetic and static friction.

Kinetic Friction: Magnitude of kinetic friction force remains constant regardless of the contact area between the surfaces. | Static Friction: The area of contact does not affect the maximum static friction force.

In a diagram of kinetic friction, label the forces acting on a block sliding to the right.

1: Applied Force (right), 2: Kinetic Friction (left), 3: Normal Force (up), 4: Weight (down)

In a diagram of static friction, label the forces acting on a stationary block with an applied force to the right.

1: Applied Force (right), 2: Static Friction (left), 3: Normal Force (up), 4: Weight (down)

Label the forces acting on a block sliding down an inclined plane with kinetic friction.

1: Weight (down), 2: Normal Force (perpendicular to plane), 3: Kinetic Friction (up the plane), 4: Component of Weight parallel to the plane (down the plane)

Label the forces acting on a block at rest on an inclined plane due to static friction.

1: Weight (down), 2: Normal Force (perpendicular to plane), 3: Static Friction (up the plane), 4: Component of Weight parallel to the plane (down the plane)

Label the forces on a free body diagram of an object being pushed horizontally with friction.

1: Applied Force (horizontal), 2: Friction Force (opposite applied force), 3: Normal Force (vertical), 4: Gravitational Force (vertical)

Define kinetic friction.

The force that opposes the motion of two surfaces sliding against each other.

Define static friction.

The force that opposes the start of motion between two surfaces in contact.

Define the coefficient of kinetic friction ( $mu_k$ ).

A dimensionless quantity representing the 'roughness' between two surfaces in kinetic friction. It relates the kinetic friction force to the normal force.

Define the coefficient of static friction ( $mu_s$ ).

A dimensionless quantity representing the 'stickiness' between two surfaces in static friction. It relates the maximum static friction force to the normal force.

Define normal force ( $F_n$ ).

The force exerted by a surface that is supporting the weight of an object. It acts perpendicular to the surface.