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Measuring the Speed of a Pitch

Date: 06/11/2002 at 01:50:16
From: Josh
Subject: how fast can I throw a baseball

Our school doesn't have a radar gun for determining how fast a 
pitcher can throw a baseball.  I need a formula so I can figure this 
out myself. 

I know the distance from the mound to the plate is 60 feet 6 inches. 
I want to get the miles per hour by using a stopwatch to measure the
time the ball takes to travel this distance.  Do you have such a

Date: 06/11/2002 at 09:14:33
From: Doctor Ian
Subject: Re: how fast can I throw a baseball

Hi Josh,

It's handy to know that 88 feet per second is the same speed as 
60 miles per hour, so if you know that the ball travels 60.5 feet 
in x seconds, you can convert that to miles per hour this way:

  60.5 feet   60 miles/hour    60.5 * 60
  --------- * -------------- = --------- miles/hour
  x seconds   88 feet/second      x * 88

Note that a ball thrown at 60 mph will take about 0.69 seconds to 
get to the plate.  What happens if your measurement is off by 
1/10 of a second?  

If you add 1/10 of a second, the measured speed will be 52.2 mph; 
if you subtract 1/10 of a second, the measured speed will be 69.9 

You also might want to take into account that 60'6" is the distance to
the pitcher's plate; but the pitcher normally releases the ball after
stepping and reaching forward from there. 

Does this help? 

- Doctor Ian, The Math Forum 
Associated Topics:
Middle School Measurement

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