Concept Library / Kinematics

Uniform Motion

Uniform motion is motion in which the object has constant velocity.

In equal time intervals, the position changes by equal amounts.

Full explanation

Uniform motion is motion in which the object has constant velocity.

In equal time intervals, the position changes by equal amounts.

Uniform motion is the simplest motion model. It means both the magnitude and direction of velocity remain constant.

If an object reverses direction, its velocity is not constant over the whole interval, even if its speed is constant before and after the turn.

Formula / representation

For uniform motion:

v = \frac{Δ s}{Δ t}

s = s_{i} + v t

Graph representations:

$s$ - $t$ graph is a straight line
$v$ - $t$ graph is a horizontal line
signed/algebraic area between the $v$ - $t$ graph and the time axis gives displacement

Units

none

Common misconceptions

Calling any motion at constant speed uniform when direction changes.
Using the constant-velocity equation for non-uniform motion.
Thinking a horizontal $v$ - $t$ graph means the object is stationary; it means constant velocity, which may be non-zero.

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