NYU Physics Demos

Shoot the Monkey!

Topics: Classical Mechanics - Projectile Motion

Equipment: Stand on wheels with electromagnet on top, target (monkey doll or metal can), leads, power supply, plastic dish with balls, blow tube mounted to wooden base with rods and clamps.

Setup: Rods, clamps and stand are already set up with blow tube. You will need to connect the power supply in series with the electromagnet and the “detector switch”, which will be moved by the ball when it is shot at the target, opening the circuit and turning off the magnet such that the target falls freely. You will need to supply a current somewhere between 0.25-0.45 Amps for a strong enough magnetic field. It is possible to roughly estimate the horizontal component of the projectile velocity, and using classical equations for projectile motion, calculate the time it will take for the target to fall to the height of the blow tube, as well as the distance between the target and blow tube, and the angle of the blow tube. Using this information one can accurately hit the target from over three meters away.

Location: On a cart near Shelf A-d2

Notes: The ball will need to hit the previously mentioned “detector switch” in order for the target to drop right as the projectile exits the blow tube. This interaction can cause the projectile to deflect, as well as slow it down. It is best to set up the switch as shown, such that the projectile will hit the switch just enough to activate it, but not enough to cause a notable impact on its motion. Click here for a video of the apparatus in use.

Keywords: Ballistic, Launch, Ball, Motion, Freefall

Ideal placement of the switch:
The Monkey:
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