why magnetic materials used in information storage should have either square or rectangularshaped hysteresis?
Horizontal distance between the curves shows that the material does not return to non-magnetised condition (a zero B) until you overshoot the H. This is called retentivity. Square/rectangular hysteresis indicates that the material has high retentivity. This means it is easily magnetised and thus remembers the direction of the last field applied to it. Compare this with the hysteresis curve of air - a straight line, indicating zero retentivity.
I googled the size, and it seems that they are low profile wide sports car tires.the measuring system is in Metric.BMW and Ferrari were what I found them to be on
