K. Allia
= K. Allia
{c}
<K. Allia> co-investigated small-sphere impacts using free-fall release and stroboscopic trajectory measurements. The joint 1994 study separated normal <coefficient of restitution>, contact <friction> and tangential <coefficient of restitution> rather than reducing every collision to one number.<Measurements of the collision properties of small spheres by S. F. Foerster and others>[Abstract and apparatus]{ref}