Flat throwing tracing experiment instrument

The utility model discloses an experimental flat parabolic motion hodoscope. A vertical plate is fixed at one side of a bracket; a ball receiver groove is fixed at the bottom of the bracket and is disposed at the front lower part of the vertical plate; an ejector cylinder is horizontally fixed at the upper end of the bracket; the front part of the ejector cylinder is transversely split to be semi-cylinders; sponge layers soaked with ink are laid on the inner walls of the semi-cylinders; a long rod is fixed on the rear end wall of the rear part of the ejector cylinder; a spring is hitched on the long rod and is buckled between a strike plate and the end wall; projecting plates are arranged at the top of the round strike plate and the top end and a forward strike block is arranged at the center of the round strike plate; long slots are respectively arranged at the corresponding places of the top wall and the bottom wall of the rear part of the ejector cylinder; the projecting plates on the strike plate stretch