This is an example of how to model the simple trajectory of a potato discharged from a potato cannon. To do this you need to have the gravitational constant, velocity of the projectile as it leaves the barrel, and the angle between the barrel and the ground.

Step 1: Finding Velocity

My first step is to find the velocity. I used the method of finding the distanced traveled per frames. Knowing the frame rate of the camera, the velocity can be calculated. In my case I calculated, as seen in the video, the velocity to be 60ft/s since it traveled 5ft in 5 frames while being filmed at 60 frames/s.

5ft * (1/5 frames) * 60 frames/s = 60ft/s

<p>You could take this experiment a step further by measuring the real world trajectory and using that data to calculate the air resistance. </p>
<p>I actually started out doing that and creating my own drag coefficient model. But it got into differential equations with conflicting x and y equations. I think I messed up with the integration so I simplified it and didn't worry about the drag, haha. But I had it narrowed down to two equations and two unknowns after putting in the initial conditions, but something was off. </p>
<p>Can you post your spreadsheets?</p>
<p>Yes I can; should be up now. </p>
<p>Thanks! </p>

About This Instructable


63 favorites


Bio: USC Mechanical Engineering student
More by showden: Post Apocalyptic Lantern Trajectory Modeling
Add instructable to: