Results for the seven balls tested are given in Figs. 2–4,
and further details are given in Table I. The force wave
forms are all of a similar general form, being an approximate
half-sine wave form, but asymmetrical in time. For most of
the balls, the maximum force is recorded at a time close to
0.5t, where t is the duration of the impact, indicating that the
experimental compression and expansion phases are of approximately
equal duration. However, the impulse during