Define kinetic friction.

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

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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.

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.

How do you calculate kinetic friction ( $F_k$ )?

$|F_k| = |mu_k F_n|$ , where $mu_k$ is the coefficient of kinetic friction and $F_n$ is the normal force.

How do you calculate the maximum static friction force ( $F_{f,s,max}$ )?

$F_{f,s,max} = mu_s F_n$ , where $mu_s$ is the coefficient of static friction and $F_n$ is the normal force.

What is the process to determine if an object will move when a force is applied, considering static friction?

Calculate the maximum static friction force ( $F_{f,s,max} = mu_s F_n$ ). 2. Compare the applied force ( $F_{applied}$ ) with the maximum static friction. 3. If $F_{applied} > F_{f,s,max}$ , the object will move; otherwise, it remains at rest.

What are the steps to solve a problem involving kinetic friction on a horizontal surface?

Draw a free-body diagram. 2. Determine the normal force ( $F_n$ ). 3. Calculate the kinetic friction force ( $F_k = mu_k F_n$ ). 4. Apply Newton's Second Law to find the net force and acceleration.

What are the steps to solve a problem involving static friction on a horizontal surface?

Draw a free-body diagram. 2. Determine the normal force ( $F_n$ ). 3. Calculate the maximum static friction force ( $F_{s,max} = mu_s F_n$ ). 4. Compare the applied force with the maximum static friction force to determine if the object moves.

All Flashcards

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.

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.

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.

How do you calculate kinetic friction ( $F_k$ )?

$|F_k| = |mu_k F_n|$ , where $mu_k$ is the coefficient of kinetic friction and $F_n$ is the normal force.

How do you calculate the maximum static friction force ( $F_{f,s,max}$ )?

$F_{f,s,max} = mu_s F_n$ , where $mu_s$ is the coefficient of static friction and $F_n$ is the normal force.

What is the process to determine if an object will move when a force is applied, considering static friction?

Calculate the maximum static friction force ( $F_{f,s,max} = mu_s F_n$ ). 2. Compare the applied force ( $F_{applied}$ ) with the maximum static friction. 3. If $F_{applied} > F_{f,s,max}$ , the object will move; otherwise, it remains at rest.

What are the steps to solve a problem involving kinetic friction on a horizontal surface?

Draw a free-body diagram. 2. Determine the normal force ( $F_n$ ). 3. Calculate the kinetic friction force ( $F_k = mu_k F_n$ ). 4. Apply Newton's Second Law to find the net force and acceleration.

What are the steps to solve a problem involving static friction on a horizontal surface?

Draw a free-body diagram. 2. Determine the normal force ( $F_n$ ). 3. Calculate the maximum static friction force ( $F_{s,max} = mu_s F_n$ ). 4. Compare the applied force with the maximum static friction force to determine if the object moves.