20070509

Physics quiz question: kilogram cube of aluminum

Physics 8A Quiz 10, Spring Semester 2007
Cuesta College, San Luis Obispo, CA

Physics 8A learning goal Q10.1

[3.0 points.] Which one of the following choices best corresponds to the side of a 1.00 kg cube of aluminum? (The density of aluminum is 2.70x10^3 kg/m3.)
(A) 0.0140 m.
(B) 0.0192 m.
(C) 0.0446 m.
(D) 0.0718 m

(Cf. Young and Freeman, University Physics, 11/e, Exercise 14.4.)

Correct answer: (D)
Density (rho) = mass/volume = m/(d^3), where d is a side of the cube. Then d = (m/rho)^(1/3). The incorrect response (C) is the radius of a 1.00 kg sphere of aluminum!

Student responses:
(A) : 1 student
(B) : 3 students
(C) : 7 students
(D) : 17 students

No comments: