# Plane Curvilinear Motion: x-y Coordinates

### Position, Displacement & Total Distance Traveled

The **position** (r) of a particle is where it is located in the plane, the** displacement **(Δr) is the change in position and the **total distance traveled** (s_{total}) is just what it says. Because a plane is 2-D, we need a vector to describe the position and displacement of a particle. The total distance traveled is a scalar.

- Position: r = xi + yj
- Displacement: Δr = r
_{final}- r_{initial}

### Velocity

Velocity is the time rate of change of position.The velocity vector is always tangent to the path curve. For example, consider a runner running on the path shown. The velocity of the runner will always be tangent to the running path.

#### What is the difference between speed and velocity?

Check all that apply.