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

I was talking about the last test of my mechanics lecture classes before the finals. I forgot to mention previously that just like with the first quiz of these classes of mine, I had to be off the campus on the days when the exam was scheduled. Thus it was someone else other than me who gave them the test.

For the second of the two tests, the first item involved the friction in one dimension with a car decelerating on a road, where they also had to use their knowledge of constant acceleration.

The second question was a continuation of the third problem from the first class. In fact, it was part on one problem in the book that I broke down so that each test would have the same number of questions. Here, following the same premise as the first part, the block on the horizontally moving mass is now placed on the hanging mass, so now the system is accelerating. If the students did consult with the earlier class about their problem, they would have found it familiar, but not exactly the same. It meant they would solve the same things the first class did, but not stop there. They had to use what the first class computed to get what was being asked of them.

The third problem was friction on an inclined plane, and just like in one of the examples we solved in class, the block was given an initial upward velocity, and thus the frictional force was downwards. Afterwards it stops moving up the slope and slides down again.

It was on that night that I made the document of the exam for their finals for the next day. This time I only had to make one exam because the two classes would be taking their finals simultaneously.

The first of five questions used a projectile with two different angles, and they were asked for the maximum height for these two angles. Then they had to prove that the energies at these maximum heights were the same. From that same principle, they had to get the maximum height of a third angle without using the equations for projectile motion.

The second was still an application of conservation of mechanical energy. A ball slides down a ramp that enters a loop. I asked them for the velocities at various points along the loop, including the first and the second time the ball passed through the bottom of the loop. This was the first problem for the entire term to which I had to give an illustration, and some of the students, surprisingly not comprehending the scenario from the words and the drawing, thought there was a large ball at the bottom of the ramp that the small ball at the top of the ramp hit, instead of a loop, despite the fact that we had no problems of that type.

The third problem had two railroad cabooses colliding and sticking together afterwards and having a final velocity. This, according to some of the students who took the test, was the easiest for them to solve, even though I did not give them the equation for the momentums before and after collision – just the equation for the momentum.

I’ll have to stop here for now and continue next time. Class dismissed.