Recent content by Andrew Mason

Whether Earth is moving toward or away from Jupiter is almost immaterial in itself. The orbital period of Io is about 42.5 hours. In that time the maximum possible change in distance between Earth and Jupiter is 15 light seconds. If the Earth is moving toward Jupiter at time t, it will be...

As Berkeman has pointed out you would need to cancel the marble’s orbital speed first in order for the marble to drop vertically to the Earth surface. The orbital speed is about 3066 m/s given by ##v=\sqrt{\frac{GM}{r}}## where r=42,164 km. So it has to lose a lot of velocity make it drop...

If the thermodynamic work done by the gas changes the polarization of the gas molecules, that would be taken into account in the change in electrical energy of the capacitor. Polarization energy would have to change the degrees of freedom or heat capacity of the gas molecules since ##\Delta...

How can you determine the gas polarization energy if you aren’t given any information about the polar nature of the gas molecules? AM

You have found an easier way to solve the problem by noticing that ##a=3/2=\gamma##, the adiabatic constant (Cp=3R;Cv=2R). So the process is equivalent to an adiabatic process:->Q=0. The work done by the gas in increasing the separation of the plates is stored as electrical potential energy of...

The use of capital V for volume and voltage is confusing. I will use lower case ##v## for voltage and upper case ##V## for volume. Your result for ##a=1.5## looks right. Since ##PV^a=\text{constant}=P_0V_0^a## and ##P=nRT/V## then ##nRTV^{a-1}=nRT_0V_0^{a-1}## so...

Just so I am clear on the linkage, the angle of BD to the extension of BC is a fixed 120° and B is free to slide along BC. You are being asked then to find the linear velocity of D and angular velocity of BD when the angle of AB to the extension of AC is 60°. The angular velocity of AB is a...

.... Wade is a journalist and has developed his own 'theories' about race and genetics. He has come under a lot of criticism for his most recent book (2014), A Troublesome Inheritance: Genes, Race, and Human History. Here is a rather uncharitable review of that book and Wade's approach...

This graphic from the paper published in Nature in 2015 may help explain the data that Reich was using: The green bars represent the proportion of genes in the populations in the stated country or region added from migrants from the steppe regions of eastern Europe and Asia (Yamnaya); The...

So 3 times the fundamental is a harmonic (a twelfth) but not 1.5 (fifth). You might find musicians who would disagree that a perfect fifth is not a harmonic interval. AM

The OP was using "overtones" to refer to the sequential harmonics above the fundamental tone. I was just doing the same. I don't think there is a hard an fast rule relating musical terms (overtones) and physics terms (harmonics). AM

It depends on whether these statements can be true: 1. "most Europeans are descended from the first settlers who arrived during the Upper Paleolithic Era. " and 2. "Only a minority arrived during the Neolithic age." by Wade and 3. "... just five thousand years ago, the people who are now the...

As someone with a long held interest in, but no academic background in, molecular biology, I find this is helpful. I became interested in the idea of using polymerase inhibitors to prevent the SARS-CoV-2 virus from replicating and started this thread in June of 2020 on Remdesivir as well as a...

There is a difference, not necessarily a total contradiction. Based on genetic analysis of European skeletons older than 5000 years, inhabitants of Europe before about 3000 BC had mixed genes from hunter-gatherers and Anatolian farmers. Both authors agree on that. Hunter-gatherers arrived in...

It was in 1933, long after Haber's 1918 Nobel prize for making nitrogen fertilizer. The reason, however, is not entirely clear. Rutherford maintained a life-long friendship with Otto Hahn, with whom he worked closely in his Montreal lab. Hahn had worked with Fritz Haber in Germany during WWI...