20080702

Physics quiz question: elapsed round-trip distances

Physics 8A Quiz 1, Spring Semester 2004
Cuesta College, San Luis Obispo, CA

Physics 8A learning goal Q1.1

(Cf. Young and Freeman, University Physics, 11/e, Exercise 1.1.)

[Version 1]

[3.0 points.] Suppose that the round-trip mileage between your home and Cuesta College is 48.0 miles. If you were to travel to and from campus five days a week, and there are 18 whole weeks of class in a semester, which one of the following choices best describes the number of semesters that you would need to drive a total of 6,000 miles between your home and campus?
(A) 0.576 semesters.
(B) 0.720 semesters.
(C) 1.39 semesters.
(D) 1.74 semesters.

Correct answer: (C)

This can be solved by ensuring that units cancel to result in 6,000 miles:

6,000 mi = (48.0 mi/1 trip) * (5 trips/1 week) * (18 weeks/1 semester) * N,

where N is the number of semesters.

Response (B) is the inverse of the correct response (C).

Student responses:
(A) : 0 students
(B) : 4 students
(C) : 31 students
(D) : 0 students

[Version 2]

[3.0 points.] Suppose that the round-trip mileage between your home and Cuesta College is 48.0 miles. If you were to travel to and from campus only four days a week, and there are 18 whole weeks of class in a semester, which one of the following choices best describes the number of semesters that you would need to drive a total of 6,000 miles between your home and campus?
(A) 0.576 semesters.
(B) 0.720 semesters.
(C) 1.39 semesters.
(D) 1.74 semesters.

Correct answer: (D)

This can be solved by ensuring that units cancel to result in 6,000 miles:

6,000 mi = (48.0 mi/1 trip) * (4 trips/1 week) * (18 weeks/1 semester) * N,

where N is the number of semesters.

Response (A) is the inverse of the correct response (D).

Student responses:
(A) : 2 students
(B) : 1 student
(C) : 1 student
(D) : 32 students

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