Net force
Net force is the vector sum of all forces acting on an object. In classical mechanics, it equals the object's mass multiplied by its acceleration.
Newton's second law: The law stating that an object's acceleration is proportional to its net force and inversely proportional to its mass. It relates net force directly to acceleration through the equation F = ma.
Force: An interaction that can change an object's motion or deform it, represented in classical mechanics by a vector. Net force combines the individual forces acting on an object.
Inclined plane: A flat surface set at an angle, commonly used to analyze motion under gravity and contact forces. Resolving gravity and the normal force shows how their vector sum drives motion along a slope.
Balanced forces: Forces whose vector sum is zero, leaving no net force on an object. Balanced forces are the zero-result case, even when several forces act.
Vector addition: The operation of combining vectors by adding their components or placing them head to tail. Net force is found by adding each force as a vector, including its direction.
Mass: A measure of an object's inertia and, in classical mechanics, the proportionality factor between net force and acceleration. For a given net force, mass determines the resulting acceleration.
Terminal velocity: The constant speed reached when drag balances the driving force on a moving object. At terminal velocity, the opposing forces make the net force zero.
Unbalanced force: A set of forces whose vector sum is nonzero and therefore produces acceleration in classical mechanics. This phrase emphasizes the condition of nonzero net force.
Free-body diagram: A diagram showing an object and the external forces acting on it as vectors. It makes the forces to be summed explicit for a chosen object.
Acceleration: The rate at which velocity changes over time, including changes in speed or direction. Net force determines acceleration in Newtonian mechanics.