# Absolute error due to reaction time when timing with a stopwatch

• Ryker
In summary, the conversation was discussing how to determine the absolute error in one swing when given the reaction time for pressing a stopwatch and the time it takes for 15 swings. After some confusion about whether to add the reaction time for each swing or not, it was clarified that the total error is 0.2 seconds and it should be divided by 15 to get the absolute error for one swing.

## Homework Statement

We are given that the reaction time for pressing the stopwatch is 0.2 s (we are measuring 15 swings, t15 = 30.45 s) and we need to determine the absolute error in one swing.

## The Attempt at a Solution

My question here is whether the absolute error for those swings is then 2 x 0.2 s = 0.4 s or is it still only 0.2 s, because the reaction times "cancel out", ie. since you're going to be within 0.2 s of proper time on your first press of the button, even if you do press 0.2 s late for the second press, you're still within 0.2 of proper time. I'm really puzzled here as to whether you need to add those or not. On one hand, I can see why you wouldn't, but then on the other hand, perhaps the reaction time error also takes into account the fact that you might press the button early.

Oh, and I also take it that t15 is irrelevant here, because

$$\delta t_{1} = \frac{1}{15}\delta t_{15}$$

Is this correct, by the way?

I think the stopwatch is only pressed after 15 swings, so it is pressed 0.2 second after the 15th swing completes.

So if you calculate the time for one swing, it is off by how much?

(This is how I understand the question.)

vertigo said:
I think the stopwatch is only pressed after 15 swings, so it is pressed 0.2 second after the 15th swing completes.

So if you calculate the time for one swing, it is off by how much?

(This is how I understand the question.)
Alright, thanks, it turns out it was meant so that 0.2 s was the total error, and you just had to divide that by 15 to get the desired absolute error for the period T.

## 1. What is absolute error due to reaction time when timing with a stopwatch?

Absolute error due to reaction time when timing with a stopwatch refers to the difference between the actual time it takes for an event to occur and the time recorded with a stopwatch. It is caused by the delay in reaction time of the person operating the stopwatch.

## 2. Why is absolute error due to reaction time important in scientific experiments?

Absolute error due to reaction time is important because it can affect the accuracy and precision of the data collected in scientific experiments. It is crucial to account for this error in order to obtain more reliable and valid results.

## 3. How can absolute error due to reaction time be minimized?

To minimize absolute error due to reaction time, it is important to have well-trained individuals operating the stopwatch and to conduct multiple trials to account for any variations in reaction time. In some cases, using more advanced timing methods such as electronic timers may also help to reduce this error.

## 4. Can absolute error due to reaction time be completely eliminated?

No, it is not possible to completely eliminate absolute error due to reaction time when timing with a stopwatch. It is a natural human limitation and can only be minimized through proper techniques and equipment.

## 5. How does absolute error due to reaction time impact the overall results of an experiment?

Absolute error due to reaction time can impact the overall results of an experiment by introducing inaccuracies and inconsistencies in the data. This can lead to incorrect conclusions and affect the validity of the study.