Displacement

Displacement measures how an object's position has changed. It tells us both how far and in which direction an object has moved from its starting position. It is a vector quantity.

In a coordinate system, we can describe an object's position using coordinates. If an object starts at initial position $x_0$ and ends at final position $x_f$, the displacement $\Delta x_1$ is:

Note: Since displacement is a vector, we should really be writing $\Delta x_{1}$ with a vector over it, such as $\Delta \vec{x}_{1}$. However, in 1D, it is pretty common to drop the vector over the variable.

In 1D, the sign of displacement indicates direction:

• Positive displacement: movement in the positive direction (right on a horizontal axis)

• Negative displacement: movement in the negative direction (left on a horizontal axis)