### A Day in the Life of John, Henry, A Traffic Cop

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Lt. Henry used a drag sled to determine that the coefficient of friction between the tires and road was 0.60. He can't use the drag sled to determine the coefficient of friction between the tires of vehicle 1 as they roll over the roadway and grass. Does he need this information? What procedure can he use to find out this information?

Using your outlined procedures, find the velocities of the two vehicles just prior to impact and estimate the coefficient of friction between the rolling tires of vehicle 1 and the roadway and grass. Be sure to state any assumptions that you make and justify them.

During the collision, which vehicle delivered the greater force of impact. Justify your reasoning using physics principles.

How can Lt. Henry determine the speeds of both vehicles just before they applied their brakes? What further information will he need?

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 "http://www.udel.edu/pbl/curric/acc12b.html" Last updated Nov. 22, 1996. Copyright Barbara Duch, Univ. of Delaware, 1993.