Calculating and Testing Human Reaction Times

 
 
Hold a dollar bill so that the midpoint hangs between a partner's fingers and challenge him/her to catch it between his/her thumb and forefingers when you release it. 

 

 
 
  1. Draw a pictorial diagram and use it to help you determine the unknown and known variables.

    2.  
  2. Calculate the time it takes for the bill to fall half its length.

    3.    (1/2 x 6 in. = 3 in.). 
     

  3. Have one person hold a meter stick and the other catch it as it is dropped between his/her fingers.  


    For each person who catches the ruler, write down the distance that the ruler falls, and convert this distance to a reaction time using the equation you used in question 2.
     


     

  4. The time (timpulse) for the necessary impulses to travel from the eye to the brain to the fingers is at least 1/7 second.  Calculate timpulse.

    5.  
  5. Compare tfall , treaction , and timpulse.  Is it possible to catch the dollar bill?

    6.  

     


Reference:

Hewitt, Paul.  (1993).  Conceptual Physics.  Harper Collins, New York, NY.


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