Unit 2: Forces - Physics Vocabulary

Force

A push or a pull

Fundamental Forces (& Name them)

Forces are classified into four categories— gravitational, electromagnetic, strong nuclear, and weak nuclear

Gravitational Force

Force of attraction between all objects

Electromagnetic Force

Force caused by electric charges

Strong Nuclear Force

Force that holds protons and neutrons together in the nucleus of an atom

Weak Nuclear Force

Force responsible for interactions involving elementary particles such as protons and neutrons

Normal Force

Force perpendicular to the surfaces of the objects in contact

Friction

Force between objects in contact and parallel to contact surfaces

Tension

Force exerted by string, ropes, fibres, and cables

System Diagram

Sketch of all the objects involved in a situation

Free-Body Diagram (FBD)

Drawing in which only the object being analyzed is drawn, with arrows showing all the forces acting on the object

Dynamics

The study of the causes of motion

Inertia

The property of matter that causes a body to resist changes in its state of motion

Resultant Force

The vector sum of all the forces acting on an object

First Law of Motion

If the net force acting on an object is zero, the object will maintain its state of rest or constant velocity

Second Law of Motion

If the external force on an object is not zero, the object accelerates in the direction of the net force, with magnitude of acceleration proportional to the magnitude of the net force and inversely proportional to the object’s mass

Third Law of Motion

For every action force, there is a reaction force equal in magnitude, but opposite in direction

Force Field

Space surrounding an object in which the object exerts a force on other objects placed in the space

Gravitational Field Strength

The amount of force per unit mass acting on objects in the gravitational field

Mass

The quantity of matter in an object

Weight

Force of gravity on an object

Law of Universal Gravity

The force of gravitational attraction between any two objects is directly proportional to the product of the masses of the objects, and inversely proportional to the square of the distance between their centers.

Static

The force that tends to prevent a stationary object from starting to move

Starting Friction

The amount of force that must be overcome to start a stationary object moving

Kinetic Friction

The force that acts against an object’s motion in a direction opposite to the direction of motion

Coefficient of Friction

Ratio of magnitude of friction to the magnitude of the normal force

Coefficient of Kinetic Friction

Ratio of the magnitude of kinetic friction to the magnitude of the normal force

Coefficient of Static Friction

Ratio of the magnitude of the maximum static friction to the magnitude of the normal force