Linear velocity

The week began with a 30 meter constant velocity RipStik run. This term the exercise was started on the sidewalk and remained on the sidewalk. A poster pad and the tablet allowed calculations to be made and graphs to be generated.

Desmos

Start for the Monday run was at the usual location at the west end of the south faculty building. Timing marks were set every three meters.

The tape measure was routed on the north side due to a puddle at 18 meters. Convective cells were bringing heavy rain showers and downburst driven wind gusts.

Wednesday operation of the split timing chronograph was covered in the A101 classroom.

The setup necessary in Desmos was also covered.

The same 30 meter stretch was used for walking.

Students then graphed their data using Desmos. In retrospect the regression equation should have been covered for both the x₁ y₁ case and for the t₁ d₁ case. A reminder that Desmos is both character and case sensitive would have been prudent, and that RMSE = 0 means character or case disagreement with the table variables. 

Milain transfers data to Desmos

This set the class up to perform the Thursday exploration of how speed interacts with slope. Oddly enough only one student surmised that the slope could change. A couple other students thought that the data points would remain on a single line, but would either space further apart on the line or condense together on the line. Both theories were suggested. Many students indicated that they did not know what would happen. There was certainly no intuitive understanding of how speed might interact with slope. In general the students do not have quantitative literacy in the sense of being able to think graphically, let alone algebraically.

Mersayes, Ashlen

A poster pad provided a white board on the sidewalk.

Due to a strong east wind, the ball was rolled westward from the 18 meter mark, with that being the new zero meter mark.

The Tripltek tablet provided capable display of the results in the field.

Ball in motion. The slow ball was timed at one meter intervals. The medium speed ball was timed at two meter intervals denoted by circles on the ends of the distance mark. 

The fast ball was moderately fast and the distance intervals were denoted by blue squares every four meters. 

Fiji, Rizal

Desmos

Desmos

With the laboratory done completely in the field, Friday will be used as an in-class wrap up day to cover zero velocity, slope as velocity, no infinite velocity, and distance as the area under a time versus velocity graph. With the two graphs next to each other. Integrating ∫ v dt produces distance = vt + d₀. 

The outlines of the Friday lecture can be glimmered from the boards above. This was the first term in which content continued into quiz day Friday. This is a broader theme across my courses: quizzes and tests are no longer in class activities. They are calendared, but when a quiz is online and is the only item on the agenda, no one shows up for class. And there no longer is a need to run these in class. 

One of the slow ball runs in the 11:00 class really slowed down markedly. 

Desmos

In the chart above the slow ball (red data) slowed down as the ball rolled. A linear y = mx equation does not work for this data. The equation one needs uses dfinal for the final distance, and r1 for the rate of decay with respect to time. 

What is happening here? The ball is slowing down and will eventually come to a stop up around 6.342 meters from the start. The speed is decreasing. The black line is the velocity. The ball starts at 1.57 m/s and the velocity drops from there, following an exponential decay curve. Eventually the velocity (speed) will drop to zero - which is what the black line is showing. So if the ball slows down, there is an equation for this situation.