title: Measuring force of a punch on iphone
body: <p>I'm creating a simple app that measures the force exerted by the user from punching in the air while holding the device. The only way I know is to use the built-in accelerometer. Now  i was able to get the acceleration values using the UIAccelerometerDelegate protocol </p>
  
  <pre><code> - (void)accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration. 
  </code></pre>
  
  <p>The problem is, I dont know what to do with these  values, for now I get the sum of x,y, and z. Is there any formula or whatsoever I could use so I could provide users a more accurate result?</p>