Final answer:
The correct option is (A). The stopwatch with an uncertainty of ±0.05 seconds is considered accurate enough for timing sprinters with close finish times such as 12.04 seconds and 12.07 seconds. Adjustments in the pendulum length of a clock can correct time inaccuracies such as gaining 5 seconds per day.
Step-by-step explanation:
The accuracy of mechanical timers varies, but for the purposes of high school-level physics, we can discuss the accuracy of a stopwatch used by a track coach. This stopwatch has an uncertainty of ±0.05 seconds, which means that any time measured with it could be up to 0.05 seconds faster or slower than the actual time.
When it comes to timing sprinters on a track team, especially in a competitive scenario where races can be won or lost by hundredths of a second, it is important to have an accurate timing device. In the case of the coach's sprint team, where there are times as close as 12.04 seconds and 12.07 seconds, this stopwatch would be considered accurate enough to differentiate between the sprint times. The uncertainty here is small compared to the differences in sprint times, allowing for confident determination of race outcomes.
In contrast, if a pendulum-driven clock gains 5.00 seconds per day, a fractional change in pendulum length must be made to correct the time. The length of a pendulum is directly related to its period of oscillation, and in turn, to the accuracy of the timekeeping. Adjusting the length of the pendulum can correct the gain or loss in time over a day.