jbriggs444's latest activity

Imagine a plane rotating like a turntable about an axis perpendicular to it. A line is drawn on this plane from the axis of rotation...

There are continuous supersonic wind tunnels after all.

Yeah, some people don't like the implication of negative pressure in the word; Absolute pressure can't be negative. But to engineers...

You're still not getting it. If we are moving inertially relative to each other then either of us could validly claim to be at rest and...

Experiment shows that an accelerating clock continues to keep accurate time. This is the "clock hypothesis". It is tested by measuring...

This is a good example of the principle of conservation of thread momentum, requiring no ongoing impulse from the OP.

And not just regardless of the speed of the source. Regardless of the speed of the observer doing the speed measurement. No matter how...

It is difficult to get a prop-driven airplane to exceed the speed of sound, yes. But a centrifugal fan should be able to produce a...

Should not the entropy from the coal power plant supplying the electricity to the motor to turn the fan more than make up the reduced...

Yes, of course. With a little bit of time to ponder, I have a different way of explaining this. "Why was there not a directional flow...

It feels like there must be a deeper reason for this. In principle, the laws of physics are symmetric and time reversible. If the input...

Yes. It is sometimes helpful to consider what happens when one takes the scenario to extremes. Suppose that we have this same 5 pound...

You have had opinions offered both ways. Both opinions are accurate. It depends on the details. Primarily on the duration of the...

Okay..i think i figured it out. Is the below correct?

Omg you are right, this is a mistake in my drawing, i must re-upload it. The right position of the points are the ones in fig.C