- #1

nathanthegreat

- 15

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**"Monkey Gun/Shoot the Monkey" Equations Question**

Hi everybody!

This is my first ever post, so if I mess something up that's why.

So here's my question. For my physics final I chose to build a Monkey Gun (also known as Shoot the Monkey). I am completely done with the gun, tree, circuit, everything, and now I am just left with the equations. I found an equation for the angle at which I need to aim the gun to hit the monkey; this equation factors in the gun height, horizontal and vertical distances between the gun and monkey, and the such. It ended up being an arc-tangent function (shocker, right?) but that's not the part I'm confused about.

What I want to be able to do is measure the distances I need to the center of the tripod on which my gun is mounted (it's a pneumatic cannon that shoots Nerf darts) from the monkey's location. Then from those numbers I will just add/subtract the distances from the end of the barrel to the tripod by dividing them into their x and y components. I already found the functions that take this into account and put them into Excel. The problem comes when I try to find the angle at which I need to fire. If I start the gun out horizontally, the numbers are about 5 meters in the x direction and 1 meter in the y direction. My function then gives me an angle of about 11 degrees. But then if I go to set my gun to 11 degrees, the horizontal and vertical distance from the end of the barrel to the monkey will be different, which would in turn give me a different angle at which I need to aim my gun. How can I manipulate my equation so it takes this into account? The angle both depends on the distances but also affects the distances, so how can I represent that mathematically in one equation?

I'm not worrying about air resistance right now, so that can just be ignored for the time being.

If I left anything out or if you need more details just let me know!

-Nathan