Re: Any experimental evidence to prove that mass increases with speed?

However, I disagree with this belief.

Well, of course you are free to disagree with this belief, or any proposition. After reading my reply, you may STILL disagree, and I can't stop you. What I am going to do is to provide several examples of actual measurements which do support the idea that some property of material objects which is related to mass does in fact increase at high speeds. What to do with this information is up to you.

You write:

I did some checking, and determined that the fastest object ever accelerated by man was a 1/10 gram object accelerated to 50 miles per second by a rail gun at Sandia Labs.

Hmmmm. I am certainly no expert in the study of high-speed projectiles, so I can't say whether this particular object is in fact that fastest MACROSCOPIC object accelerated to very high speed in a controlled manner by scientists (I am certain that objects have been accelerated briefly to higher speeds in uncontrolled explosions, but of course we can't really watch them carefully). In any case, a speed of 50 miles per second corresponds to only a teeny-tiny fraction of the speed of light: about 0.03 percent of c, as a matter of fact. Special relativity predicts that the changes in the mass (or momentum, or kinetic energy) of an object become significant only much closer to the speed of light: 20 or 30 or 50 percent of c. So I would not expect scientists to be able to measure any special relativistic changes -- or the lack thereof -- in a ball shot at 50 miles per second.

However, scientists can, and have, accelerated MICROSCOPIC objects to much, much higher speeds. High-energy physicists routinely shoot electrons, protons, neutrons, entire atoms, sometimes even simple molecules, at speeds of 50 percent of c, or 90 percent of c, or even 99.99 percent of c. At these speeds, the changes predicted by special relativity are enormous: the mass (or momentum, or kinetic energy) of a particle may increase by a factor of 2, or 10, or 100.

Simple example number 1: in 1964, William Bertozzi published the description of a simple experiment in the American Journal of Physics (vol 32, p 551). He used a van de Graff generator to give electrons high kinetic energies, fired them down an 8-meter-long tunnel, and measured the time it took them to reach the far end. You can read an account of this experiment on one of my course web pages:

http://spiff.rit.edu/classes/phys314/lectures/relmom/relmom.html

If the mass of an electron remained constant, he should have found a constant relationship between the speed of an electron, v, and its kinetic energy, KE:

                        2
      KE  =  0.5 * m * v

But his measurements showed that this formula did NOT work at high energies: the KE grew very rapidly for even small increases in speed when that speed was near the speed of light. One way to interpret this is that the mass of the electron was growing as it approached the speed of light. Einstein's theory predicts a particular relationship between mass and speed which fits the measurements pretty well.

Simple example number 2: in the early part of the twentieth century, when high-energy physics got its start, scientists tried to build devices to accelerate particles faster and faster. The earliest accelerators were pretty small: they could fit on a large table-top. If you go to the library or the web, you can find lots of information about "cyclotrons", as these early devices were named; they were called that because they used magnetic and electric fields to move charged particles around in circles.

Now, as the devices grew bigger and more powerful, scientists found that they were not getting the large increases in particle speed they expected. For some reason, the design principles which worked at relatively low speeds failed to accelerate particles properly at speeds near c. Once the basic cyclotron design was modified to account for an increasing mass of the particles, however, physicists found they could get the expected speeds again. This modification turned ordinary cyclotrons into "synchro-cyclotrons". You can read more about this evolution in many books; a good web site is

http://synchrotronsbasic.net/

All the big modern circular accelerators, such as Fermilab or CERN, are based on a design which assumes that mass (or momentum) increases at relativistic speeds. If it didn't, they wouldn't work.