PASCO Monkey and Hunter, 1D60.30

Topic and Concept:

• Motion in Two Dimensions, [:MotionIn2D#ProjectileMotion: 1D60. Projectile Motion]

Location:

• Cabinet: [:MechanicsCabinet:Mechanic (ME)]

• Bay: [:MechanicsCabinetBayA5:(A5)]

• Shelf: #1

attachment:MonkeyHunterSetup02-400.jpg

Abstract:

This is the Pasco's version of "Shot the Target". A target (in this case a stuffed monkey) is released about 2 meters above the table top as soon as a projectile (a Ball) is fired. The ball then hits the target in midair as long as the system is properly alined.

Important Setup Notes:

• This demonstration will require practice - the failure rate for this demo is ~5%.
• Do not connect monkey to magnet until ready for use - metal attachment tends to become magnetized over periods of 30 minutes which inhibits the dropping mechanism.
• Too much light incident on the photogate may cause the triggering mechanism to malfunction. Try to keep stage lights somewhat dim.

Setup and Procedure:

1. Mount the support rod to the lecture bench.
2. Mount the launcher on opposite end of lecture bench with clamps.
3. Connect the power cord and telephone wire.
4. Connect the photogate to the launcher and connect its respective wires.
5. Alignment - look through the bottom of the launcher (not down the launching end!). There is a cross-hair - use this to aim at the monkey. After gun is aligned, tighten set screws.
6. Make sure the triggering system is not yet armed - the red light should be off. Otherwise, the photogate could trigger a premature drop of the monkey.
7. Attach the monkey to the electromagnet. A ladder will most likely be needed.
8. Load the projectile into the launcher. Use the black rod (~28 cm in length) to push the projectile into the barrel to the desired spring setting. This is demonstrated in the video linked below. There are three such settings. The spring will click each time a new setting is reached.

Cautions, Warnings, or Safety Concerns:

• DO NOT look down the barrel of the projectile launcher - a spontaneous launch could take your eye!
• Take care to not aim the projectile launcher at or near the audience; also keep in mind the possible post-contact trajectories of the projectile.

Discussion:

The Pasco projectile launcher is carefully aimed at a stuffed monkey by look through the bottom of the launcher and using the cross-hair to target the monkey. The target is held up by an electromagnet which is coupled to the launcher via the PASCO interface and a photogate. The instant the projectile is launched through the photogate, the monkey is dropped. Since the monkey and the projectile are falling at the same rate, the projectile will hit the monkey in midair. The launcher has 3 spring settings so that you can show the students that this is independent to the particle's velocity.

When ready to fire the projectile, arm the triggering system - the red light will turn on. Pull the release cord to fire.

Videos:

• [http://youtu.be/DIebxpYWL-g PASCO Monkey and Hunter, 1D60.30 ]

• [https://www.youtube.com/user/LectureDemostrations/videos?view=1 Lecture Demonstration's Youtube Channel]

References:

• [http://www.pasco.com/physhigh/shoot-the-target.cfm PASCO item page]

• [http://sprott.physics.wisc.edu/demobook/intro.htm Clinton Sprott]

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