If mass increases with velocity why does the gravity remain the same?

Question

when an electron passes through a flourescent tube why is the gas not atracted to it

Answer 1

The electron cannot travel at the speed of light.

And no it is not the weight which is increased, it is the mass as you correctly stated it.

Answer 2

Is it me or r these 2 separate questions??

A1) i think you've confused velocity with acceleration
F=ma and a=mv^2
so gravity = mass x (mass(velocity squared))
so mass stays constant, gravitational force remains constant, acceleration remains constant so velocity increases.

A2) when an electron passes through a fluourescent tube the electron is attracted to the gas. The energy from the electrode excites the electrons in the gas molecule(higher energy level) so that they emit light (lower energy level) and more energy in the form of heat and photons so that the gas forms part of the current and emits light - thats how the fluorescent tube works. A fluorescent tube wouldn't work without the gas.

Answer 3

Mass of electron = 9.1 x10^ (-31) kg.

If it moves with a speed of 0.9c, its mass is
23 x10^ (-31) kg.

The gravitational force is 2.2 x 10 ^ (-29) N.

At this speed the electron takes a time of 7.4 x 10^(-9) second to cross 2 meter length.

Since the acceleration due to gravity remains the same irrespective of mass, it is 9.8 m/s^2.

The distance the electron will travel due to gravitational force is 2.7 x 10 (-16) m
= 2.7 x 10 (-19) milli meter.

Compared to the electric force acting on electron this gravitational force does not produce any appreciable effect.

Note also that the acceleration due to gravity remains the same as 9.8 m/s^2 on the electron, whether you consider the relativistic mass or not.

Another point is electrons are not moving with this speed inside the tube light. They do have drift velocity which is very small compared to the velocity of light



Thank you very much EYEONTHES. Since I cannot mail you I use this to thank you.

Answer 4

Hmmm.

Well. Gravity is a 'weak' force at best of times - we only experience a significant gravitational effect on earth due to the planet's large mass.

The mass of an electron is 9.10938188 × 10^31 kilograms. Insignificant (relatively speaking).

Plus, for these relativistic effects (such as mass increase) a body really needs to be travelling at a speed close to that of light.

edit: In response to K_Biz -

If you were to travel at a speed tending towards that of light, indeed the theory states that you would experience the relativistic effect of mass gain. This is different however to the conditions under which black holes operate - they specifically consist of a huge amount of mass compressed into a singularity. Therefore you would not become a black hole, just a more massive version of yourself travelling at a great speed.... theoretically.

Answer 5

I'm not very sure, but from what I know from school the electron, you're talking about, travels very fast and hits gas particles in its way. Every time that hits another particle looses energy and velocity. So you're electron never gets to the point to attract bigger particles.
Please take a look at a basic nuclear physics book for a detailed explanation.
PS: I'm sorry to say this pearl but you're theory don't work in this case. WE have multidirectional movement and multiple collision processes. This is more of a stop and go type of travel for the mentioned electron. But the calculations you mentioned are real and accurate. It is no chance for this electrons to get to the point to beat gravitational forces. Yes it is possible in a nuclear accelerator, but with no gas around it.

Answer 6

The tube is evacuated, isn't it? Besides, electrons are extermely light - about 2000 times lighter than a proton I think.

But this is a very good question. I have always wondered the answer to this question. Einstein said that as a body approaches the speed of light, its mass approaches infinity. Well if that is true, then its gravitational force should approach infinity also, right? Eventually you would have a black hole, and everything would be sucked in.

If anyone could answer this question, that would be great.

Answer 7

Looks like a rehash of the old 'eotvos experiment' At these ranges in a fluorescent tube, any observed increase in the gravitational mass increase of the electron as opposed to an increase in its inertial mass would be swamped by the EM forces.
If you examine the orbit of Mercury, which astronomers did, you will find that it precesses. Einstein explained this by his special theory of relativity. The inertial mass of Mercury increases as it gets closer (and faster) to the Sun in its elliptic, but so does the gravitational force which explains the precession of its orbit

Answer 8

It's aconstant pressure exerted. Mass increasing with the velocity of an object pertains to that object moving through the atmosphere available. You could say gravity is inert in that way

Answer 9

The gas is attracted to it, all matter attract each other, but the speed of the electron is not relativisic so it's mass does not go up that much.

Answer 10

Mass does n't increase with velocity,momentum does.