Diffractometer and method for diffraction analysis making use of two Euler cradles, a primary and a secondary Euler cradle. Through the use of the device of the present invention, exercisers are able to perform push-ups that meet predetermined range of motion criteria regardless of their body characteristics and receive feedback based upon whether the exercise was properly performed or not. The system is configured to charge a first subset of storage cells from a storage comprising a serial arrangement of storage cells. The cuttings will contain sand and other hard andor corrosive substances that will erode the surfaces of the bearings and shorten their useful life. In addition, the present invention provides an accompanying method of detecting an endpoint during the polishing process by detecting a change between a first rotational strain and a second rotational strain with the rotational strain sensor. The side wall is formed with at least one horizontally throughgoing hole having an annular inner edge.