抄録
Analysing the photographs of the ricochet motion, the following results were obtained. (1) The mean hydrodynamical impulsive force is practically independent of the incident angle except for the blunt head projectile. (2) The horizontal component of the force becomes smaller as the incident angle increases and the projectile becomes hard to ricochet as the component nears zero. (3) The point of application of the force recedes as the incident angle increases. (4) The vertical velocity component of the projectile after the ricochet is generally greater than that before.
Furthermore a coefficient of retardation, a coefficient of ricochet, and a coefficient of slip were newly introduced in order to compare the ricochet motion with the motion of repulsing upon a solid wall.
