45.  The drawing shows a device that you can make with a piece of cardboard, which can be used to measure a person’s reaction time. Hold the card at the top and suddenly drop it. Ask a friend to try to catch the card between his or her thumb and index finger. Initially, your friend’s fingers must be level with the asterisks at the bottom. By noting where your friend catches the card, you can determine his or her reaction time in milliseconds (ms). Calculate the distances d1, d2, and d3.

w0085a

 

Card starts from rest and the acceleration is due to gravity

 

Now plug in the various times and find the distances

 

 

 

 

Final Answers are:

 

 

 

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This page last updated on January 11, 2020