Which puck requires the greatest force to stop in the same time interval: A with 2 m/s, B with 4 m/s, or C with 6 m/s?

The force required to stop each puck in the same time interval can be determined using Newton's second law of motion, which states that force equals mass times acceleration (F = ma). When applying this to the problem, we also consider the change in velocity and the time over which that change occurs.

To stop each puck, the change in momentum (mass times velocity) must be accounted for. The greater the initial velocity of the puck, the greater the change in momentum required to bring it to a stop. As pucks A, B, and C have respective velocities of 2 m/s, 4 m/s, and 6 m/s, they require different amounts of force to halt their motion within the same duration.

Puck C, traveling at the highest speed of 6 m/s, will have the largest change in momentum. Given that force must be applied over the same time interval to stop all three, the puck with the highest initial velocity requires the greatest force to achieve this change in motion. In essence, since C has a higher velocity compared to A and B, it necessitates a greater force to stop it in the same time frame.

Thus, the answer is that puck C, moving at 6 m/s, requires