Motion & Change
11 concepts in Physics
Motion and change is the study of how objects move through space and time. Students learn to describe motion precisely using concepts like position, displacement, speed, velocity, and acceleration. They work with motion graphs — position vs. time and velocity vs. time — to visualize and analyze movement patterns. This topic covers uniform motion, uniformly accelerated motion, and projectile motion, building a progressively richer picture of how the physical world behaves. The kinematic equations give students powerful tools for predicting where an object will be and how fast it will be moving at any future time. Understanding motion is the starting point for all of mechanics and connects directly to real-world contexts such as driving, athletics, space travel, and the motion of celestial bodies.
Suggested learning path: Start with describing motion qualitatively using everyday examples, then learn to interpret and create motion graphs, and finally apply kinematic equations to solve quantitative problems.
Position
The location of an object relative to a reference point, described using coordinates.
Displacement
The change in position from a starting point to an ending point, including both magnitude and direction.
Velocity
The rate of change of position with respect to time, including both magnitude and direction.
Speed
The rate at which distance is covered over time, without regard to direction of travel.
Acceleration
The rate at which an object's velocity changes over time, including changes in speed or direction.
Free Fall
Motion under the influence of gravity alone, with no air resistance acting on the object.
Projectile Motion
Motion of an object thrown or launched, moving under gravity with an initial velocity.
Circular Motion
Motion along a circular path at constant speed, with continuously changing direction.
Reference Frame
A coordinate system used to describe positions and motions, relative to an observer.
Vectors
Mathematical quantities that have both a magnitude (size) and a direction, represented as arrows in diagrams.
Angular Velocity
The rate at which an object rotates about an axis, measured in radians per second, with a direction along the axis.