MECHANICS - MOTION IN TWO DIMENSIONS - PROJECTILE MOTION NC State University Faculty Access

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Monkey and Hunter
# 1D60.30


Description:

The Monkey and Hunter demonstration is a classic way to show how gravity affects a projectile. A hunter aims a gun directly at a monkey hanging from a tree limb. The monkey decides to outsmart the hunter by releasing its grip on the tree the instant it sees the flash of the muzzle. The monkey thinks that that gravity will pull it down and the bullet will fly over its head. However, as we all know, the bullet is accelerated downward by gravity at the same rate as the monkey and the bullet still hits it.

For years the physics department would shoot a projectile at a stuffed monkey. Using photogates, the stuffed monkey would be released at the moment the projectile left the gun. This was a very dramatic demonstration. A little too dramatic for some. As the story goes, the department received a cease and desist order on behalf of a certain animal rights group. Apparently shooting a toy monkey is just as bad as shooting a real one. Considering that this is a classic physics demonstration, a substitute for the monkey had to be found. The university paid a consulting firm several thousand dollars to determine the one thing we could shoot which would offend absolutely nobody. They found it.

The following semester, we introduced the UNC-CH mascot to the cheers of students everywhere. We have also had success with a certain blue devil from time to time.



Instructions: This demo will be set and aimed when you arrive. The aiming will have been done using the metal plate, so the use of the UNC Ram will potentially need some adjustments.
(1) Place the ball in the cannon;
(2) Hold the back of the cannon to steady it;
(3) Use the plunger and force the ball all the way back;
(4) Switch the control box over to "arm" (a red light will light);
(5) Hang the target from the magnet;
(6) Pull up on the yellow launching string slowly.
(7) Switch control box to "disarm."
Repeat steps 1-7 for another shot.

Hazards: The target is held by a small permanent magnet that releases the target when a pulse of current disrupts the feild. If the support is shaken, the target may fall. Please do not linger beneath the target.

Parts: Shoot the monkey apparatus
Metal target
Tarheel

Purchased/Built: purchased

Quant. in Demo Room: 2

Source: Pasco Scientific

Demo References
The Video Encyclopedia of Physics Demonstrations Disc 02-02 The apparatus consists of a blow gun with dowel projectile and electromagnetic release.
Hilton M-13a Shoot the tin can monkey with a blowgun and an electromagnet release.
Freier and Anderson Mb-16 A compressed air gun shoots at a tin can.
The American Journal of Physics AJP 36(4),367 Use a large bore air gun and wood "shell" projectile which is caught in a net.

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