# Day 142: How Hot Are Your Hot Wheels?

The class did two things today, well, I did one and the class did the other.  We discussed the conceptual part of their summative impulse and momentum test.  All of my tests have two components; a conceptual part which is mostly multiple choice (at a higher DOK than simple recall) and a problem set.  The conceptual part is usually about 10 or 15 MC and there are usually one or two problems depending in how many objectives being assessed.  On this recent test, there was an impulse problem and a conservation of momentum problem.  On each test I also provide an opportunity for the students to really challenge themselves by providing a choice of two problems that both address the same objective.  For example, on this recent test the student could choose to do a pretty standard run-of-the-mill explosion problem or a ballistic pendulum problem.

This time we did not discuss the problems.  Rather, I am going to have the students make corrections on the problem(s) they will re-assess in addition to some posted practice problems.

After discussing the multiple choice component we moved to WB’ing the practice sheet putting all the components of the charge model together. We really did not get so far, only through the series of pictures to explain charging by conduction. We will finish it tomorrow.

General Physics:

We had a practice COE assessment and the started a COE activity that has two parts.  The activity is based on this problem from the assigned practice:

The basic premise is whether or not 10% dissipated is a realistic value.  To test it, we are using Hot Wheels and track to recreate the problem.  Essentially, they will solve for the Energy dissipated by taking the difference between the initial gravitational energy and the final kinetic energy.  The velocity is measured at the bottom of the track/ramp with a photogate.

The follow-up will be to have the students use the values from this part of the activity to predict the velocity of the car at some spot along the ramp that I place the photogate.