# gp4rts

### When and why did this custom start?

It is not considered "proper" to applaud between movements of a symphony or concerto. Yet at one time it was ok. Does anyone know when and why this changed? Oddly, applause after big arias in opera is expected, even in operas where there the music flows continuously (e.g. Wagner, Puccini) and the orchestra has to stop to wait for the applause to finish. But in a symphony or concerto, when there is a complete stop to the music, it's a no-no. At a concert tonight, the audience applauded after the first movement of the piano concerto played by Yefim Bronfman. At that point he stood up and took a bow, and made as if to leave the stage. The conductor joked "there will be three encores (the concerto has 4 movements). The program notes said that applause between movements is "...something that priggish custom now forbids."

I would appreciate any comments or suggested references.

5 AnswersClassical1 decade ago### Please check my work--rolling ball?

I recently responded to this question http://answers.yahoo.com/question/?qid=2... , and after two tries I think I have the right solution. Find it here http://img172.imageshack.us/img172/1094/bowlingbal...

The reason I think there is a mistake is when initial and final energy of the ball are subtracted, that does not match the frictional energy. See this

http://img172.imageshack.us/img172/3005/bowlingbal...

Any ideas or suggestions welcome

2 AnswersPhysics1 decade ago### Math programs for Mac?

I have been using an old version of MathCad on my Mac for some time. It runs under OS 9. I am planning an upgrade to a newer version of OS X that does not allow booting OS 9, and MathCad apparently no longer supports Mac. I would like to find a math program for the Max at a reasonable price (about $100). Any suggestions?

1 AnswerMathematics1 decade ago### Math programs for Mac?

I have been using an old version of MathCad on my Mac for some time. It runs under OS 9. I am planning an upgrade to a newer version of OS X that does not allow booting OS 9, and MathCad apparently no longer supports Mac. I would like to find a math program for the Max at a reasonable price (about $100). Any suggestions?

1 AnswerSoftware1 decade ago### What is this piece?

A melody I heard long ago. I once knew the name, but I have forgotten it.

http://youtube.com/watch?v=_p7bMZnJZ9k

3 AnswersClassical1 decade ago### Application of Gauss Law?

I am applying Gauss' Law to an elementary situation: A sphere of radius r containing a uniform charge density rho, with an electric field normal to the surface of constant value E. Gauss' Law has two forms, integral and differential. See http://en.wikipedia.org/wiki/Gauss%27_law In the integral form, the surface integral of E (normal component) equals the total charge enclosed divided by e0. Since E is constant, the surface integral result is just E times the surface area 4*pi*r^2*E. The total charge enclosed is rho times the spherical volume, or (4/3)*pi*r^3*rho; therefore 4*pi*r^2*E = (4/3)*pi*r^3*rho/e0. The result is E=(1/3)*r*rho/e0.

The other form is div(D)=rho, or div(E)=rho/e0. In spherical coordinates div(E)=(1/r^2)d/dr(r^2*E). For E=constant, this is (1/r^2)*(E*2*r), or 2*E/r. So using the differential form I get

E=(1/2)*r*rho/e0.

One method gives a 1/3 multiplier, the other a 1/2 multiplier. What am I doing wrong? Which one is right?

1 AnswerPhysics1 decade ago### Road toll due from 2yrs ago in Italy?

I received a notice that I failed to pay a road toll in Italy two years ago. Apparently they got a photo of the rental car's license and found me. This may have happened, as I think I remember there was a malfunctioning toll machine in one location. What happens if I ignore it? What can they do? Anyone have this experience?

2 AnswersOther - Europe1 decade ago### Mass or weight: does 1 liter of water have a mass of one kg or does it weigh one kg?

If I want to determine the motion of an object that weighs 1kg, what is the number to use as its mass? If that object is one liter of water, isn't its mass also 1 kg? If someone tells me that an object weighs W kilograms and I want to know its acceleration if I apply 1 Newton, what mass value do I use: W kg? W/g ?

6 AnswersPhysics1 decade ago