Combining the speed with the direction of the arrow, you get its velocity. This can be a very handy tool in such a calculation. Acceleration Acceleration is the increase of velocity over a period of time. Deceleration is the decrease of velocity. In conclusion Motion is change in position.
All motion is relative to some fixed point or object.
Speed is a measurement of that change in position over time. Velocity is speed in a given direction. Vectors help to determine the sum of velocities. Acceleration is the increase in speed or velocity over a period of time. Deceleration is the decrease of speed or velocity over time.