velocities
If youve ever seen a kayak move down a fast-moving river, you know that remaining in the same place would be hard. The river current pulls the kayak along. Pushing the oars back against the water can move the kayak forward in the water, but that only accounts for part of the velocity. The kayaks motion is an example of classical addition of velocities. In classical physics, velocities add as vectors. The kayaks velocity is the vector sum of its velocity relative to the water and the waters velocity relative to the riverbank.