In our last meeting we reviewed the absolutely mission critical idea of **vector**. For a wonderful discussion of the idea of vector and the history of the development of the concept of vector quantities you should watch this video — https://www.learner.org/vod/vod_window.html?pid=552. For completeness and for reference purposes, we list below a short summary of vector quantities you should be able to easily identify in one and two dimensions:

- position
- displacement $$ \Delta r = r_{final} – r_{initial}$$
- velocity $$ \lim_{\Delta t \to 0} \frac{\Delta r }{\Delta t}$$
- acceleration $$ \lim_{\Delta t \to 0} \frac{\Delta v }{\Delta t} $$

You should also understand what is meant by the concept of uniform acceleration. This is the assumption we made in order to determine the equations of motion for projectiles. Basically, acceleration is said to be uniform when it is constant.