title: What unit of measurement is userAcceleration returned in?
body: <p>I'm creating an iOS app that uses the values of <code>CMDeviceMotion.userAcceleration</code>. That is, the acceleration that the user is giving to the device without gravity.</p>
  
  <p>I'm just wondering, what unit of measurement are the acceleration values returned in? Is it m/s^2, or is it determined by the <code>deviceMotionUpdateInterval</code>? I can't find anything about it in the Apple developer docs.</p>