AbstractIn a study of the transient behavior of a series of nylon 6/6 yarns differing systematically in mechanical properties, the effects of high‐speed, transverse missile impact upon yarn specimens were observed by high‐speed photography. The loss in missile kinetic energy was determined directly from the reduction in missile velocity and was studied as a function of yarn tenacity and missile impact velocity. The shape of the missile energy loss curves was due to the partition of missile energy into yarn kinetic energy and yarn strain energy. The missile energy losses and yarn dynamic breaking strains were compared to static breaking energies and breaking strains for these yarns. The observed trends are discussed in terms of the differing yarn tenacities and test ra