Acceleration Meter provides you with real-time information from the iPhone’s accelerometer. Isaac Newton would have loved this application!

This app also tells you the maximum recorded acceleration for each session, and enables you to reset the maximum force. Also, useful visual and numerical information regarding each of the axis’ acceleration is provided, as is a total force, which is the pythagorean sum of all three axis.

Note that the total acceleration is usually around 1 g, which is 9.8 meters per seconds squared [9.8 m/s^2]. However, this varies slightly in accordance with latitude, altitude, and local topography.