swansont

The net force is always in the direction of the acceleration, but this doesn't mean that it has to be in the direction of the displacement (which is given by the velocity vector) "Diagonal" motion is just an artifact of a coordinate system, which is arbitrary.

I've got one at work My G4 cube was neat looking, but needed to be replaced, and is now happily toiling as our fax server.

Mac G4 dual 867 MHz, 1 GB RAM.

e is the fraction of the original energy (measured above the first step, or mgH) that is retained. You should be able to set up a simple equation with that information.

If you want the bounce height relative to the stairs to be equal, then the ball has to lose the energy it gained in one step on each bounce. So if the height of a step is a, it loses mga of energy in each bounce.

There's not an absolute cutoff, though, so the choice is somewhat arbitrary for saying what the visible range is. The eye efficiency looks sorta gaussian, but a lot of the time a linear scale is shown, rather than a log scale, which makes it look like the efficiency goes to zero at 400nm and 700nm. I've used lasers at 780 nm and could see diffuse reflections at low power (a few mW). I've also seen 852 nm light (a few hundred mW source) which made me realize that I wasn't wearing my laser goggles.

The drag depends only on the speed of the object. If you increase your thrust, your speed will increase but then so will the drag, until you reach the speed where they are equal. Then the net force will be zero, and speed will be constant.

This is called anomalous dispersion. No violations of causality occurred.

Evolution doesn't have to be gradual to that extent. A mutation that proves to be beneficial will tend to spread through a population and this will take time, but not necessarily millions of years. (Keep in mind that it's really the number of generations that matter, and many organisms have shorter life cycle times than humans do.)

I think any of the noble gases will act like ideal gases, since they don't form molecules. Others will too, to varying degrees.

A ml is a cm3

The drag equation uses v2 because the force depends on the square of the speed. If you go twice as fast, the drag is 4 times bigger. That's what has been observed to hold. You don't use v because it doesn't depend linearly on v. There is probably a theory that shows why the term is v2, but if anyone here knew it they'd probably have posted it by now. If I had to guess, I'd say that it's a combination of imparting momentum to air molecules by collision, which depends on the relative speed, and trying to compress/do work on the air (or whatever fluid) which would also depend on the relative speed. So you end up with a combination of the two effects, which is nonlinear and thus depends on v2. Again, this is a guess.

Interesting in what way?

It's an astrological "effect," not an astronomical one, associated with Mercury going retrograde. That is, Mercury's path appears to change direction, because of its different orbital speed with respect to ours. Apparently astrologers associate Mercury with communication. There's nothing real to this.

This is certainly an extreme example that demonstrates your point, but even if the bullet were launched at below terminal speed, it would come down slower due to air resistance. Some of the original KE is lost to the air on the way up, and then even more is lost on the way down, so KEground, initial>PEzenith>KEground, final The final speed has to be smaller than the launch speed, assuming no change in mass.

That was part of my concern. I don't have the ability to nudge someone either way - it would be a shove. But it should be more than just disagreeing. I'm not about to ding somebody for having a different opinion or for an argument about semantics. It's going to have to be for bad science. And it's two dots at the moment. Somebody didn't like one of my answers.