Understanding Friction and Free-Body Diagrams

Friction

Force opposing motion between surfaces.

Static Friction

Friction preventing motion; variable up to a limit.

Kinetic Friction

Friction acting on moving objects; always less than static.

Coefficient of Friction (μ)

Ratio indicating friction between two surfaces.

Free-body Diagram (FBD)

Visual representation of forces acting on an object.

Normal Force (FN)

Force perpendicular to the surface supporting an object.

Weight (FW)

Force due to gravity acting on an object's mass.

Inertia

Resistance of an object to change its state of motion.

Net Force (Fnet)

Total force acting on an object after all forces are combined.

Acceleration (a)

Rate of change of velocity; calculated as Fnet/m.

Tension

Force transmitted through a rope or cable.

Mass (m)

Amount of matter in an object, measured in kg.

Force of Gravity (FW = mg)

Weight calculated by mass times gravitational acceleration.

Friction Force (FF)

Force resisting the motion of an object.

Applied Force

Force exerted on an object to move it.

Surface Type

Material characteristics affecting friction levels.

Example of Friction

Rubber on concrete has high friction coefficient.

Free Fall

Motion of an object under the influence of gravity alone.

Air Resistance

Force opposing motion through air; affects falling objects.

Force Calculation

Fnet = mass × acceleration; used in problem-solving.

Friction in Skydiving

Air resistance increases with speed until terminal velocity.