A Historical Quest: The Monkey and the Hunter

A hunter wants to shoot a monkey hanging from a tree branch, hence he aims his blowpipe at the animal. As soon as the monkey sees the arrow coming out of it, it loosens the grip to avoid being shot.  The hunter, as the monkey jumps, thinks he missed the target; shortly thereafter, however, he can see with great surprise the arrow hit the free falling animal.  It is possible to demonstrate that the monkey would be hit in all cases, whatever the velocity v0 at which the arrow moves, provided that its value is such as to allow the arrow to hit the animal before it reaches the ground. In apparatus 1422, at the very instant in which the projectile exits the cannon, the photocell positioned on the muzzle sends a signal, deactivating the electromagnet which holds the polystyrene ball used to simulate the monkey. If the condition mentioned above is satisfied, while falling, the polystyrene ball will be hit by the projectile in any case.  The apparatus we offer you is particularly sturdy. Moreover, the anodized aluminum cannon can be rotated and is characterized by a thick high pressure bilaminates base.  This apparatus was entirely realized in our factory, from the production of its components to mounting.

Supplied Materials:

1 Modular rod (lower part) with flat washer and handwheel

1 Modular rod (upper part) with knurler to fix the electromagnet

1 Tripod base 1 Folding ruler

1 Launching device

1 Photogate with cable

1 6V 2.5A power supply

2 Balls 2 Clip

1 Electromagnet with core

1 Stand for electromagnet

1 Transducer

1 Cable for electromagnet

1 Laser pointer

2 Polystyrene balls

2 Metallic pins

1 Didactic guide 1 Box