Friction

Friction

A force that opposes the motion of an object due to the surfaces in contact.

Frictional Force

A force that opposes the motion of an object, arising from the interaction of two surfaces.

Coefficient of Friction (µ)

A rating system that indicates the roughness or smoothness of surfaces; it is unitleless and ranges from 0 to 1.

Normal Force (FN)

The upward force exerted by a surface to support the weight of an object resting on it.

Static Friction

The friction that exists when an object is at rest and not moving.

Kinetic Friction

The frictional force that occurs when two objects are sliding against each other.

Net Force (Fnet)

The overall force acting on an object, calculated by subtracting the force of friction from the applied force.

Force of Friction (Ff)

The resistive force that opposes the motion of an object, calculated as Ff = µFN.

Example of Static Friction Formula

Ff < µsFN ; Ff = Fpull for static friction.

Example of Kinetic Friction Formula

Ff = µKFN for kinetic friction when moving at constant velocity.

Perfectly Frictionless Surface

A surface with a coefficient of friction of 0, resulting in no resistance to motion.

Acceleration

The rate of change of velocity of an object, often expressed in m/s².

Free Body Diagram

A graphical representation showing all the forces acting on an object.

Unit of Force

Newton (N), the unit used to measure force.

Fpull

The applied force acting on an object, which can be countered by friction.

Weight of an Object

The force exerted on an object due to gravity, calculated as weight = mass × gravitational acceleration.