Motion is one of the fundamental concepts in physics. It describes how objects change their position over time. We see motion everywhere - from the simple movement of a ball rolling across the floor to the complex orbital motion of planets around the sun. Understanding motion helps us describe and predict how things move in our world.
There are three main types of motion we commonly observe. Linear motion occurs when objects move in straight lines, like a car driving down a highway. Rotational motion happens when objects spin around an axis, such as a wheel turning or the Earth rotating. Oscillatory motion involves repetitive back-and-forth movement, like a pendulum swinging or a guitar string vibrating.
Position tells us where an object is located relative to a reference point. Displacement, however, is the change in position from one point to another. Unlike distance, displacement is a vector quantity, meaning it has both magnitude and direction. The displacement vector points directly from the initial position to the final position, regardless of the path taken.
Speed and velocity are related but different concepts. Speed tells us how fast something is moving and is always positive. Velocity, however, includes direction information and can be positive or negative. When an object moves in a straight line, positive velocity means moving forward, while negative velocity means moving backward. The magnitude of velocity equals speed.