A uniform disk of mass m and radius R floats in outer space and spins about its symmetry axis at angular speed !0 . Along the symmetry axis, there is a massless stick, which happens to be length R as well (see diagram). A point mass also of mass m with velocity v0 perpendicular to the symmetry axis hits the end of the stick and embeds itself, forming one rigid body of mass 2m. The incoming speed is v0 = !0 R