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 the second meeting of my mechanics lecture class for the eleventh week of the second term, I returned their exams to them, and since the scores were all between ten and twenty five for a fifty point quiz, I decided to forgo the new lesson and teach them how to solve all of the problems in their last test.

Most of the problems were straightforward substitution. To facilitate the solutions I marked off the several points along the object (or projectile’s) trajectory that were required in various sub-items in the problem and labeled them with letters.

This was also to show that for each time that they used an equation, they could only use the horizontal and vertical displacement, horizontal and vertical velocity, angle and time associated with that point.

Values with different letter subscripts cannot be used in different equations.

When we got to the second problem, in which they had to solve a minimum of two equations in two unknowns before they could proceed, there were several questions again on how I got the final value, even though we had a similar (and more complicated) example before and that it was something they were supposed to be all too familiar with in their Mathematical Methods One, Trigonometry, Analytical Geometry and Differential Calculus, which are all required before they could take the subject I was teaching, since they were all engineering majors and following a stricter mathematics flowchart than the other courses.

Is it because the example was more difficult that their brains “naturally” rejected all or most parts of it, that they could not associate its solution with the relatively simpler problem?

Or do they need several (probably at least five) examples to be able to detect the pattern correctly? This solution would take up entirely too much class time, and even if I gave them the written solved problems, what is the assurance that they would study them – at least early enough from when I give it such that they could ask me about it sometime before the day of the exam itself in which it will appear.

From their questions while we were solving, it also seems that they were concentrating too much on the steps for simplifying the systems of equations, which again they should be familiar with already from their previous math subjects, but are also methods that are not set in stone but are variable depending on how the equations are substituted. And the equations used may change in different problems.

I will have to come up with a new way to get them to practice more solving.

Session 873 failed the last test. Class dismissed.