Recent content by EspressoDan

Yes, wheel speed is not important. But, a lot of replies here state that the important factor is the the forward speed of the aircraft, or the thrust of the engines. Fundamentally, the problem has to do with neither, the only important factor is the speed of the airflow over the wings. Engines...

A $5 ultrasonic sensor and an Arduino is what you need. All you need at the tank is a 5v supply, which I'd do with batteries for this. Just turn the Arduino on to take a reading and off when you're done, should last years. Mount the ultrasonic sensor inside the access hatch pointing at the...

How deep is the tank?

Depends on the flow-rate from the tap.

From an aerodynamic perspective, think about the two forms of Drag. Parasitic Drag and Lift Dependent Drag. Given that this is a symmetrical aerofoil, it won't be producing any lift at zero angle of attack. However, given the shape of it it might be worth considering the effect that the...

Really, the answer has more to do with the container that the water is in and the starting conditions (volume and temperature). It's an engineering question. The surface areas presented by the sides of the container, the surface area at the top and the thermal conductivity of the materials will...

Found a thread with the answer here: https://www.physicsforums.com/threads/where-do-photons-actually-come-from.882217/#post-5545439

https://www.physicsforums.com/threads/sound-and-heat-whats-the-difference.333439/

Hello, I have a short question: In relation to the Sun - is Black-body radiation ultimately the result of a combination of spontaneous (majority) and stimulated (minority) emission of photons? In relation to the IR emissions from everyday objects due to their temperature - is Black-body...

Thank you for the recommendations. Your recommendation reminded me that I have a copy of 'The Character of Physical Law' on the shelf! I've purchased 'Relativity and Commonsense', for the amazing 1987 open-universityesq cover alone! An Illustrated Guide to Relativity looks interesting too...

Hi, I'm reading "Hidden in plain sight". The book, like most other layman's texts has a particular frustration for me. Most layman's book try to relate concepts to human experience with analogous examples. The problem they cause me is that when discussing concepts like time and space the...

Thanks. You need to know what paradox you're worrying about to know what paradox you're worrying about! The FAQ was useful, the Doppler-shift answer worked for me.

Hi, I'm reading a book explaining relativity. I previously understood the subject in layman's terms but am now confused. The author has introduced relative motion in an invariant universe with the concept that motion through space is only relative to the observer. Given this, I'm now...