## 20111022

### Physics quiz question: Ford Mustang GT Premium kinetic energy

Physics 205A Quiz 4, fall semester 2011
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 6.17

"First Test: 2011 Ford Mustang GT"
Motor Trend Channel
youtu.be/ydykiWKW6fE

A 2011 Ford Mustang GT Premium (mass 1,640 kg) takes 10.3 s to accelerate from rest to 45.0 m/s on a horizontal track[*]. What is the final kinetic energy of this car?
(A) 7.38×104 J.
(B) 7.23×105 J.
(C) 7.60×105 J.
(D) 1.66×106 J.

Correct answer (highlight to unhide): (D)

The final (translational) kinetic energy of the car is given by:

KEtr,f = (1/2)·m·(vf)2,

KEtr,f = (1/2)·(1,640 kg)·(45.0 m/s)2 = 1,660,500 J,

or to three significant figures, 1.66×106 J.

(Response (A) is m·vf, response (B) is m·g·vf, response (C) is m·vf·t.)

Sections 70854, 70855
Exam code: quiz04iMpL
(A) : 2 students
(B) : 7 students
(C) : 4 students
(D) : 38 students

Success level: 75%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.64