Among other things, it will allow us to predict what the velocity of a particle will be at a certain time. It will also allow us to predict the position of a particle at that time.

    Once again, for simplicity, we will consider only motion in one dimension. In essence, this is motion along a line. In addition, we will also only consider the case of motion with a constant acceleration. If you are not comfortable with the notion of a constant acceleration, please review this section above.

    In the constant acceleration section above, we were able to predict the velocity of a particle without resorting to any mathematical formulae. However, we were unable to predict the position of the particle. In fact, predicting the position of a particle undergoing constant acceleration requires knowledge of calculus. However, do not be alarmed by that fact. All we need are the results obtained from calculus, and we won't actually do any calculus.

    Let me quote the formulae that we can derive from calculus concerning constant acceleration and motion in one dimension

Before we proceed, let me stress one point. If you take a physics course in the future, you will be introduced to many formulae. It is not enough to memorize the formulae, but you must know when they apply and under what conditions you can use them.

    For instance, these formulae only apply to the case of a particle moving under constant acceleration. If this condition does not apply to the situation under consideration, then you cannot use these formulae.

    Finally, let me say something about the units involved with these formulae. In fact, we have spent an entire section above on units. Since we are now using S.I. units, the following are the appropriate units to use for the quantities in these formulae.

Units

• The unit for distances is meters.
• The unit for velocity is meters/sec.
• The unit for acceleration is (meters/sec)/sec.
• The unit for time is seconds.

If you stay consistent with the use of these units, the answer that you get will be in the appropriate units. For instance, let's say you are solving for the velocity of a particle. If you use the appropriate units for everything else, the answer you get for velocity will be in "meters/sec". If on the other hand, you are solving for acceleration, the answer you get for acceleration will be in "(meters/sec)/sec" if you use the appropriate units for everything else.