050 RipStik force is change in momentum

The class opened in A101 with Newton's definition of force as the change in momentum.

Then the demonstration was diagrammed. 

The numeric values were added after the two RipStik runs. 

This term two timers timed the change in momentum and two timers timed the 1.8 meter final velocity speed trap. The only measurement is the 1.8 meter speed trap.

Once again the spring scale was attached to jute tied to a post partway up the slope.

The downslope force was measured at ten to twelve Newtons.

The runs began at the first post the sidewalk intersection. The distance is roughly 21 meters to the bottom end of the speed trap.


The calculations were all made on the white board, the Smartboard was not used nor was the spreadsheet. The spreadsheet was updated after class. The difference of 4% is vanishingly small relative to past differences. 

Students timed both the change in momentum time and the speed trap time. That the agreement was within 4% was not something that could be engineered. The result was a surprise for everyone

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