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

Mechanics lecture make up session, first day, thirteenth week of classes, third trimester: I prepared four examples to discuss with them for inclined or two dimensional friction.

The first example was important because it showed an object being pushed up a slope. The students therefore saw that it was possible for the friction to be pointed down an incline. They also had to make two free body diagrams: one for the downward motion and another for the upward. And they had to learn what quantities are constant for both cases: which are just the coefficient of friction, the angle of the incline and the mass. Everything else (friction, summation of forces parallel to the surface) changed values.

The second example was significant because it introduced the concept that the force acting on an object being subjected to friction need not be horizontal, but may be at an angle.

The third example had two objects connected by a pulley, one of which was hanging freely and the other on a surface. It showed them that tension is still included in the test (and not just weight and constant acceleration). Just like with the Atwood’s Machine setup, they had to make one free body diagram for each object that is exerted by forces, which is two.

The last example also had two objects again connected by a pulley, but here they are both on surfaces, just that one is on a tilted frictionless surface.

I intentionally wrote down the first three problems on the board first so that my discussion of them would be quicker, except that now, the same two students I mentioned before who were mumbling to each other during the exam were complaining that I was talking too fast.

Of course I was going by the comprehension of those who have been listening since the start of term and are therefore very familiar with the basic concepts. Besides, I still did pause every once in a while to ask if everything was clear. Other people asked questions and they didn’t. So I was assuming they understood.

Towards the end there were also some students (both high scoring and failing) who were just talking – and they were seated in front. So I just skimmed through that part of the solution.

I also gave them the last part of the last problem as an exercise.

Another major development during the session was that I agreed that our next meeting would not be the exam but the discussion of the topics for the finals. It is in the meeting after that (the last one for the term) that we will have our last exam.

Some of the students were noisily grateful for this because of the pile op of their requirements during the day of our original schedule. Not that I acted all deserving of their gratitude. My workload is the same either way.

I’ll talk about my second to the last Advanced Mathematics session next time. For now, class dismissed.