Student "edition" found at {csi dot journalspace dot com}.

Maybe I shouldn't have started this blog now, not with everything that's been going on.

In my first mechanics lecture meeting for the fifth week of classes, I followed up on the recent first experiment in the lab, which was about Uniform Acceleration.

Here, one of the questions in the quiz was about what provided the acceleration in the experiment. Several students, admittedly not having read the manual, instinctively – and correctly – answered gravity.

So I went to the second aspect of the topic of Constant Acceleration in One Dimension, which is vertical otherwise known as free fall.

I told them that the convention we were going to use is that displacement is now represented by y instead of x, since we are dealing with a whole different axis in the Cartesian plane.

Also, I said that in each and every case of vertical motion, the acceleration would now have a standard value of negative nine point eight meters per second squared.

At this point I had to explain how this is different from the negative acceleration used in horizontal motion. There, if an object such as a car is decelerating, when the velocity reaches zero it stops. In vertical motion it was not the same case, but I said I would have to clarify in a later part of the discussion.

I also had to emphasize that the direction of the velocity in this case would determine its sign: positive for up and negative for down.

I told them there were three scenarios for this type of motion, but I concentrated on the first one: when an object is dropped.

The constants, I said here, were that the initial velocity of the object is zero, at any time after that the velocity would be negative and increasing in numerical value, but technically still less than the original given that any negative number (since the velocity would always be pointed downwards) is less than zero.

Time, as usual, is always greater than or equal to zero and always increasing, and displacement would be negative, because the initial position is always higher than any position afterwards.

For the first time, I also did not give an exercise, since with the near minimum class size, I could already tell when everyone was in attendance, even without a record book for remembering it. The students also considered that as a relief.

Session 803 also passes up the period exercise at this point. Class dismissed.