All Flashcards
Compare and contrast static and kinetic friction.
Static Friction: Acts on stationary objects, prevents motion, adjustable up to a maximum value. | Kinetic Friction: Acts on moving objects, opposes motion, constant value.
What are the key differences between and ?
: Coefficient of static friction, applies to objects at rest, usually greater than . | : Coefficient of kinetic friction, applies to objects in motion, usually less than .
Compare the force of static friction to the applied force before movement occurs.
Static Friction: Equal in magnitude and opposite in direction to the applied force, up to the maximum static friction force. | Applied Force: The external force attempting to initiate movement.
Compare the force of kinetic friction to the applied force when an object is moving at a constant velocity.
Kinetic Friction: Equal in magnitude and opposite in direction to the net applied force. | Applied Force: The external force that, in combination with kinetic friction, results in zero net force and constant velocity.
Compare the effect of surface area on static vs kinetic friction.
Static Friction: Magnitude is independent of the contact area between the surfaces. | Kinetic Friction: Magnitude is independent of the contact area between the surfaces.
What is the effect of increasing the normal force on kinetic friction?
Increasing the normal force increases the magnitude of the kinetic friction force.
What happens when the applied force exceeds the maximum static friction?
The object begins to move, and kinetic friction takes over.
What is the effect of friction on the work-energy theorem?
Friction does negative work, converting kinetic energy into thermal energy, thus reducing the total mechanical energy.
What happens when a car tire rolls without slipping?
Static friction between the tire and the road provides the centripetal force needed for circular motion.
What is the effect of a higher coefficient of static friction between two surfaces?
It requires a greater force to initiate movement between the surfaces.
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 ().
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 ().
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 ().
The force exerted by a surface that is supporting the weight of an object. It acts perpendicular to the surface.