Recent content by ahiddenvariable

Your question can be answered in the same way that Thomas Aquinas' "first cause" proof of God is invalidated. His argument is that, since we always observe that any given event has a cause before it, it's necessarily true that there must be a First Cause that started the whole chain of events...

Are the holes below the liquid surface and you want the same mass flow of liquid through each hole? What is the hole above the liquid surface for? Please try to state exactly what you want to do, without expecting us to guess.

We observe that the visible matter of galaxies is moving in ways that cannot be attributed to only the gravitational forces associated with this visible matter and conclude that there must be additional gravitational forces caused by matter we can't see. As I understand it, gravitational forces...

There are some ways. Electronically, it's easy, and there are such devices, called leak detectors. You point them in the direction you think there might be a leak in a pressurized system and it will detect ultrasound leaks, translating them to a hiss at a frequency within ear range. If your...

At one point, we had a lot of left over Silicon Nitride shapes in the lab. They were used in a project development of ceramic armour, with acrynom WHISTLE. Anyway, the surfaces of these blocks were micro-machined to very good flatness and smoothness, and in fact, we used them to sharpen razor...

Anachronist (A name I like.): It seems to me that a bullet shape is basically like a simplified rocket shape minus the fins, and as you suggest, the fins can cause significant increased drag. Remember, a large part of fin operation is the drag they create. Because they are thin, they don't...

Okay, I understand what you want to do. It's not easy to make such calculations on arbitrary 3-D shapes, but some are harder than others. There are complications that arise with transitions from laminar flow to turbulent flow, and these transitions at the surface of the body can cause huge...

In principle, yes, pure metals can cold weld; however, you need to have very clean and smooth surfaces. Most metals have oxide coatings that inhibit such welding, and most surfaces do not experience intimate contact when pressed together because extremely small unevenness causes only relatively...

Experience has shown that the drag force on an object in a fluid stream is proportional to the dynamic pressure, 1/2*rho*V^2, and the drag coefficient is the empirically determined constant of proportionality. Experiment has shown that this proportionality constant is usually well defined for a...

The way I resolve this issue both mathematically and intuitively is to recall that a sum of an infinite series of fractions can be finite. For a convergent series, this it true. For a divergent series, this is not true. Take the convergent series 1/2 + 1/4 + 1/8 + ... The sum of this series...