Final answer:
The new stopwatch with an uncertainty of ±0.05 seconds will not be helpful for timing the track team as its precision is insufficient to distinguish the small time differences between sprinters.
Step-by-step explanation:
A high school track coach has purchased a new stopwatch with an uncertainty of ±0.05 seconds. Since runners on the track team typically record times that can be within hundredths of a second of each other, the level of precision of the timing device is crucial for accurate assessment. For example, during the school’s last track meet, the first-place sprinter finished with a time of 12.04 seconds, and the second-place sprinter came in at 12.07 seconds. The difference between their times is 0.03 seconds, which is smaller than the stopwatch’s uncertainty of 0.05 seconds. Therefore, the new stopwatch will not be helpful in distinguishing times with such close margins as it cannot reliably resolve differences of less than 0.05 seconds.
Extrinsic feedback is information that is received from an external source, such as a coach or a stopwatch, to determine the performance or execution of a skill. In this case, all of the options -- a stopwatch, a coach, and a videocamera -- can be sources of extrinsic feedback. A stopwatch can be used to measure the time taken to complete a task, a coach can provide feedback and guidance based on observation, and a videocamera can capture a performance for later analysis and feedback.