Calculating Minimum Required Velocity

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The discussion revolves around calculating the minimum initial velocity required for a projectile to land on top of a building located at a specific distance and height. The problem is framed as a projectile motion challenge, emphasizing the need to determine both the minimum initial velocity and the launch angle. While standard projectile equations are acknowledged, the complexity of the problem is highlighted, particularly in finding the correct parameters. One participant claims to have found a solution on Wikipedia and plans to share it after allowing others time to explore the problem. The conversation underscores the theoretical nature of the inquiry, despite it not being a requirement for any coursework.
ByronT
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This is a tough question. I'd like to know if anybody can find a good solution. It isn't required for any of my classes, but I'd like to see a theoretical result. It seems like it should be a simple projectile motion problem, but it's not that easy.

Let's say there's a building x1 meters away and y1 meters tall. So, we only know x and y. What is the minimum initial velocity at which a projectile can be launched to "land" on top of this building? Assume that the projectile is launched from the origin.

Obviously, we know the standard projectile equations. We know the x-distance and y-distance we must travel. We know how to convert vinitial to vx and vy. But how do we find the minimum vinitial and its corresponding theta?

Any help would be appreciated.
 
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So you want the projectile to be able to stop on top of the building, not just clear it?
 
I figured it out. Found something on Wikipedia. I'll let other people look at it for a day before I post what I found.
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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