Physics midterm question: Bugatti Veyron vs. Eurofighter Typhoon

Physics 205A Midterm 1, fall semester 2013
Cuesta College, San Luis Obispo, CA

"Bugatti Veyron vs Euro Fighter - Top Gear - BBC"
TopGear
youtu.be/7NZ9X9A2efA?t=6m20s

A car and a jet plane start a one-mile round-trip race from the same starting point[*]. As the jet plane returns back to the starting point, the car has approximately 100 feet yet to cover to return to the starting point. From the starting time to when the jet plane crosses the finish line (thus officially ending the race), discuss why the jet plane has a faster average speed, but a slower average velocity magnitude compared to the car. Explain your reasoning by using the properties of position, distance traveled, displacement, velocity, and speed.

[*] "Bugatti Veyron vs. Euro Fighter Typhoon Drag Race," BBC Top Gear Series 10, Episode 3 (2008), 06:20ff.

Solution and grading rubric:

• p:
  Correct. Understands the difference between average speed (distance traveled over elapsed time) and magnitude of average velocity (magnitude of displacement over elapsed time). Thus from the starting to the jet's finish time, the jet will have a greater average speed (more distance traveled over the same elapsed time) compared to the car (less distance traveled over the same elapsed time); but the jet will have an average velocity magnitude of zero (zero displacement) compared to the car ("100 ft" over the elapsed time).
• r:
  As (p), but argument indirectly, weakly, or only by definition supports the statement to be proven, or has minor inconsistencies or loopholes. May argue that the jet has a greater average speed than the car, as the jet traveled farther in less time, or the jet traveled the same distance in less time than the car; while still understanding that the jet's average velocity magnitude would be zero (and thus less than the car's average velocity magnitude).
• t:
  Nearly correct, but argument has conceptual errors, or is incomplete. At least understands distinction between definition of average speed and magnitude of average velocity, and some attempt at comparing distance traveled, displacement, and elapsed time.
• v:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. At least some attempt of relating distance traveled, displacement, and elapsed time with average speed and magnitude of average velocity.
• x:
  Implementation/application of ideas, but credit given for effort rather than merit. Application of concenpts other than those of comparing distance traveled, displacement, and elapsed time.
• y:
  Irrelevant discussion/effectively blank.
• z:
  Blank.
  

Grading distribution:
Sections 70854, 70855, 73320
Exam code: midterm01p0To
p: 23 students
r: 20 students
t: 21 students
v: 8 students
x: 1 student
y: 0 students
z: 0 students

A sample "p" response (from student 0494):