Forces - Key Vocabulary

Vocabulary flashcards covering force concepts from the notes.

Force

A push or pull that occurs when two objects interact; has magnitude and direction; measured in Newtons (N).

Vector quantity

A quantity that has both magnitude and direction; forces are vectors.

Magnitude

The size or strength of a force.

Direction

The path along which a force acts; can be up, down, left, right, or at an angle.

Contact force

A force that occurs when objects physically touch; examples include friction, air resistance, and tension; includes the normal force.

Normal force

The perpendicular contact force exerted by a surface on an object, pushing it away from the surface.

Friction

A force that opposes motion between two contacting surfaces.

Air resistance (drag)

A friction-like force that opposes the motion of a body through air.

Tension

A pulling force transmitted through a string, rope, or cable when it is taut.

Non-contact force

A force that acts without direct contact; examples include gravity, magnetic force, and electrostatic force.

Gravity

A non-contact force that attracts masses toward each other; on Earth it pulls objects toward the ground.

Magnetic force

A non-contact force exerted by magnets; can attract or repel and acts at a distance.

Electrostatic force

A non-contact force between electric charges that can attract or repel; strength decreases with distance.

Attract

A force that pulls objects toward each other (e.g., gravity, magnetic attraction).

Repel

A force that pushes objects apart (e.g., like magnetic poles).

Distance effect on force

For gravitational, magnetic, and electrostatic forces, increasing distance weakens the force.

Unit of force

Newton (N) – the SI unit of force; 1 N accelerates a 1 kg mass by 1 m/s².

Reaction force

The force exerted by a surface back on an object in contact; part of Newton's third law; opposite to the applied force.

Surface

The boundary between two objects that enables contact forces such as the normal force.