In physics or physical science, acceleration ( (symbol: a ) is a vector quantity which is defined as as the rate of change of velocity. An object is accelerating if it is changing its velocity. In SI units, acceleration is measured in metres/second² (m·s-²) using an accelerometer.
An accelerometer is a is an electromechanical device for measuring acceleration.An accelerometer inherently measures its own motion , in contrast to a device based on remote sensing.These forces may be static, like the constant force of gravity pulling at your feet, or they could be dynamic - caused by moving or vibrating the accelerometer.Texas instruments has a great accelerometer guide, including how to do some of the necessary math.
The average acceleration is the ratio between the change in velocity and the time interval.
The instantaneous acceleration at any time may be obtained by taking the limit of the average acceleration as the time interval approaches zero. This is the derivative of the velocity with respect to time:
Acceleration and accelerometer applications
Using accelerometers in machine condition monitoring: Monitor and predict the health and condition of moving machinery.
The Wii Remote for the Nintendo Wii console contains accelerometers for measuring movement and tilt to complement its pointer functionality.
Within the last several years, Nike, Polar and other companies have produced and marketed sports watches for runners that include footpods, containing accelerometers to help determine the speed and distance for the runner wearing the unit.