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.

 

Speed is the same as velocity?
Speed is the magnitude of velocity?
Speed is always positive.