Linear motion
Linear motion is the movement of an object along a straight-line path in a single spatial dimension, where the velocity vector does not continuously change direction.[1] This form of motion, also known as rectilinear motion, serves as a foundational concept in kinematics, the study of motion without regard to its causes.[2] It enables the description of an object's position using a single coordinate, typically denoted as x, as a function of time t.[3] Key quantities in linear motion include displacement (Δx), the change in position; velocity (v), the rate of change of position; and acceleration (a), the rate of change of velocity.[2] Mathematically, instantaneous velocity is the first derivative of position with respect to time, expressed as v = \frac{dx}{dt}, while acceleration is the first derivative of velocity, a = \frac{dv}{dt}.[2] For cases of constant acceleration, a set of kinematic equations relates these variables to predict an object's trajectory.[4] These equations are:- Final velocity: v = v_0 + at
- Position: x = x_0 + v_0 t + \frac{1}{2} a t^2
- Velocity squared: v^2 = v_0^2 + 2a(x - x_0)
- Average velocity form: x = x_0 + \frac{(v_0 + v)}{2} t