  In this paper, we report a novel experimental and theoretical study to
examine the response of a soft capsule bathed in a liquid environment to sudden
external impacts. Taking an egg yolk as an example, we found that the soft
matter is not sensitive to translational impacts, but is very sensitive to
rotational, especially decelerating-rotational impacts, during which the
centrifugal force and the shape of the membrane together play a critical role
causing the deformation of the soft object. This finding, as the first study of
its kind, reveals the fundamental physics behind the motion and deformation of
a membrane-bound soft object, e.g., egg yolk, cells, soft brain matter, etc.,
in response to external impacts.
