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Here's some basic information about normal airplanes. There needs to be an upward-turning tendency, known as decalage. You can accomplish this by putting a little upward bend in your straw. Then, it needs to be slightly nose-heavy. If it isn't, it will follow a scalloped up-down path, or even fly backwards. If you get those right, it will find its natural ...

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You are mostly correct that the dimples on a golf ball reduce its drag by promoting transition from laminar to turbulent flow, which reduces the size of the separated wake behind the ball. But that doesn't mean that a different ball would benefit in a similar way. The Reynolds number (Density * Speed * Diameter / Viscosity) has to be within a certain range ...

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The main difference is that a ping-pong ball travels a much shorter distance over a much shorter time. Initial velocity is a function only of its mass and the bat's hitting power. At the end of its very short flight of a second or less, its final velocity is not a major factor and it does not have time to slow down significantly enough to matter. Spin ...

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In potential flow there is no boundary layer. Therefore, no separation, either. Regarding pressure: In potential flow you have two stagnation points, on in the front and the second in the back. Both experience stagnation pressure. Between both, pressure will vary greatly and only total pressure will be constant. An airfoil presents an obstacle to the air and ...

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They need a particular amount of wing area, in order to get the desired amount of wing loading (weight per unit of area) at the speed they want to fly. Then, drag is minimized if the aspect ratio (ratio of wing length to wing width) is maximized. So at a given area, they want long narrow wings.

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It certainly does not have topspin at any point. The first reason is correct. It has less backspin and therefore appears to drop. The camera angle from behind the pitcher is deceiving. Although it appears to drop off suddenly, it is more gradual than it appears. A straight fastball defies gravity quite a bit, as does a split fingered fastball, because they ...

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For this to understand let us consider a room in place of a hose say of length $l$ in which a ball is bouncing up and down and colliding elastically with the ceiling and the floor continuously. Now if we increase the speed of the ball in this upward or downward direction using some techniques, the ball will strike the ceiling and the floor with a greater ...

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Understand the concept of a Lift Vector. It is not just UP, but it depends on the angle of the wing. When the wing moves down, it is angled to provide forward as well as vertical force. Same when it moves up. Of course in an airplane with a propeller, the propeller just goes up and down. So how can it provide forward thrust? You can figure that out.

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Yes, there is and it's surprisingly easy! First determine which target are you trying to reach, as it will alter the necessary trajectory. The most fuel-efficient trajectory, broadly speaking, is the Hohmann maneuver, however it is also the most time-consuming (you could travel faster, yet less fuel-efficiently; or use gravity assists for more efficiency and ...

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