AP Physics 1: Unit 2 Part 1 - Inertia and Forces

Inertia

The property responsible for an object’s resistance to changes in motion; the natural tendency of an object to remain at rest or at constant velocity.

Mass

The quantitative measure of an object’s inertia, indicating how much ‘stuff’ is contained in the object; standard unit is kilogram (kg).

Weight

The force of gravity exerted on a mass by the Earth or another astronomical body, designated by Fg; calculated as Fg=mg.

Force

A push or pull capable of accelerating an object; standard unit is the newton (N), where 1 N = 1 kg m/s².

Normal Force (FN)

The force exerted on an object by a surface, always perpendicular to that surface.

Tension Force (FT)

The force in a string, rope, or cable that is pulling or suspending an object.

Frictional Force (Ff)

The force that occurs between two surfaces and opposes the motion of an object; characterized by static and kinetic friction.

Static Friction

The force that must be overcome to start an object moving; maximum static friction is given by Ff, max=sFN.

Kinetic Friction

The force required to keep an object moving; given by Ff=kFN.

Drag Force (FD)

The force of air resistance acting against an object moving through a fluid; given by FD=bv.

Free-Body Diagram (FBD)

A visual representation of all forces acting on an object, showing the magnitude and direction of each force.

Terminal Velocity

The constant speed reached by an object when the drag force equals the gravitational force, resulting in no further acceleration.

Gravitational Force (Fg)

The force exerted by a planet or astronomical body on a mass, causing it to have weight.

Applied Force (FA)

The force applied to an object by a person or another object, regardless of whether there is physical contact.

Coefficient of Friction (μ)

A measure of how much friction exists between two surfaces; ranges from 0 to 1, with lower values indicating more slippery surfaces.