Two hockey players, Aaron and Brunnhilde, are pushing two pucks on a frictionless ice rink. The pucks are initially at rest on the starting line. (Figure 1) Brunnhilde is pushing puck B, which has a mass three times as great as that of puck A, which Aaron is pushing. The players exert equal constant forces of magnitude on their pucks, directed horizontally, towards the finish line. They start pushing at the same time, and each player pushes his or her puck until it crosses the finish line, a distance away.
Part A. Which puck reaches the finish line first?
a. Both pucks reach the finish line at the same time.
b. Puck A reaches the finish line first.
c. Puck B reaches the finish line first.
d. More information is needed to answer this question.
Part B. Let be the magnitude of the kinetic energy of puck A at the instant it reaches the finish line. Similarly, is the magnitude of the kinetic energy of puck B at the (possibly different) instant it reaches the finish line. Which of the following statements is true?
a.
b.
c.
d. You need more information to decide.