An essential part of projectile studies is the 'Monkey and Hunter' problem.
A monkey sees a hunter take aim. If he lets go when the hunter fires will he drop so that the bullet passes harmlessly overhead; or should he sit still and watch the bullet pass harmlessly underneath since it is pulled down by the gravitational field? This apparatus allows for an interactive study of the problem by students.
An elastic powered 'gun' fires ping pong ball 'bullets' at a model monkey supported from a small electromagnet.
The electromagnet is switched off at the instant the projectile leaves the gun. Both monkey and bullet fall at the same rate and the bullet hits the monkey. The system has everything required except a low voltage power supply and laboratory stand for the electromagnet.