Physics: Key Concepts in Force, Motion, and Acceleration

Acceleration

The rate of change in velocity; speeding up, slowing down, or changing direction

Acceleration Due to Gravity

The constant acceleration on an object because of gravitational force; on Earth it is 9.81 m/s2.

Balanced Force

A situation where the net force on a system is zero

Force

An interaction between an object and another object or a field that acts to change the motion of the object

Frictional Force

A force that resists the relative motion of two objects or substances sliding against one another

Macroscopic

At a scale large enough to be seen with the naked eye

Mass

A measure of how much matter is present in a substance

Motion

The change in an object's position with respect to time and in comparison to the positions of other objects used as reference points

Net Force

The overall force acting on a system or object after opposing or balanced forces cancel each other out

Newton (N)

The SI unit of force, or mass times acceleration

Newton's Second Law of Motion

The law stating the relationship between the force applied to an object and the object's mass and acceleration

Speed

The measurement of the rate of change of position with respect to time

Unbalanced Force

A situation where the net force on a system is not zero

Vector Quantity

A quantity with both a magnitude and a direction

Velocity

The rate of change of position of an object moving in a specific direction