Lab Activity: Reaction Time
In this lab you will determine a method for measuring your reaction time and then use this measurement to solve a motion problem. Reaction time is defined as the amount of time that passes between the reception of a mental stimulus and the behavioral response that follows. Research has shown that, for humans around 20 years of age, average reaction time for an audible stimulus is approximately 160 ms while that for visual stimulus is approximately 190 ms. 
Your job in this lab us to determine a procedure wherein you can use a standard 12 inch ruler, a partner, and your understanding of free fall kinematics, to determine visual reaction time. Once a methodology is chosen, make measurements for several trials and then average the results. Record the details of this activity in your lab notebook, including your calculations. If you are having trouble coming up with a method, click here to see one option.
Now that you have data on your reaction time (and your partner's), use an online reaction time test (click here) to compare your results with those you will generate at that website. Determine the percent difference between the reaction times you measured with the ruler and those you determined using the online test.
Finally, use the reaction times you measured with the ruler to calculate the answer to the following problem:
You are driving down the road in your car at 20 m/s. All of a sudden you see a deer jump out onto the road in front of you and it doesn't move. If the maximum negative acceleration for your braking system is -4.6 m/s2 determine the minimum distance that the deer can be at the moment you see it, and still not be hit by your car. Repeat the calculation with the average reaction time of your partner. Please note that there are two parts to this solution, not just one. Click here to see the solution or to compare your answer to mine.