## anonymous one year ago Does the weight of a vehicle get heavier with speed? & Why?

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1. anonymous

Yes mass becomes greater as the the velocity increases

2. anonymous

How and why?

3. anonymous

&& I'm talking about weight not mass!

4. anonymous

Oh weight is defined by the gravitational pool

5. anonymous

pull*

6. anonymous

So if you go faster then centripetal acceleration will increase

7. anonymous

oh by the way weight doesn't change by velocity

8. anonymous

in special relativity mass is the one that changes depending on the velocity of that objectt

9. anonymous

weigh comes as a result of gravitational pull which doesn't vary if the object is assumed to be equidistant from the initial point ok?

10. anonymous

Ignore the centripetal acceleration crap I snapped

11. anonymous

equidistant to the radius of the object

12. anonymous

Hey yo irish boy what's your take on this ?

13. IrishBoy123

hi @Robert136 i am a bit warey about getting stuck in as i think it is more complicated that first appears, certainly to me $$E = E_0 \gamma$$ looks easy, ie if the OP's car is travelling at v m/s, plug v into $$\large \frac{m_oc^2}{1 - \frac{v^2}{c^2}}$$ and, for someone in a stationary reference frame, you're done. mass increases, very slightly of course. but to an observer standing on the sun, her car is travelling at 80,000mph (ignoring the acceleration/ non inertial) ; and in the OP's reference frame both the earth and the sun should increase in mass as they are moving relative to the car. and she shouldn't notice any time dilation/length contraction/mass increase in her reference frame , it's the things moving relative to her that will appear "weird". that's a headful of headache for me lol!!!

14. IrishBoy123

@Michele_Laino has written a tutorial on spesh rel. we have an expert in the forum, should that be needed :p

15. anonymous

As others above have said, it's actually a very subtle, technical issue. For the effect you're mentioning, you actually need to use Einstein's general relativity formalism to understand gravitational effects and how they're related to mass and gravitational acceleration. See the "simple examples of mass in general relativity" section on Wikipedia: https://en.wikipedia.org/wiki/Mass_in_general_relativity#Questions.2C_answers.2C_and_simple_examples_of_mass_in_general_relativity There, they address specifically how a hot object would indeed have greater gravitational attraction than a cold object, because of the increased thermal energy (which is ultimately motion of the molecules). In the same vain, a moving object would experience an altered gravitational pull, although there doesn't appear to be a consistent explanation or calculation involved. It gets hard to define the definite question you could ask. One quote from the wikipedia page:"The only difference between the "hot" and "cold" systems in our last question is due to the motion of the particles in the gas inside the pressure vessel. Doesn't this imply that a moving particle has "more gravity" than a stationary particle? This remark is probably true in essence, but it is difficult to quantify. Unfortunately, it is not clear how to measure the "gravitational field" of a single relativistically moving object. It is clear that it is possible to view gravity as a force when one has a stationary metric - but the metric associated with a moving mass is not stationary."

16. anonymous

This is just the rest of that Wikipedia section, might as well post it too: "While definitional and measurement issues constrain our ability to quantify the gravitational field of a moving mass, one can measure and quantify the effect of motion on tidal gravitational forces. When one does so, one finds that the tidal gravity of a moving mass is not spherically symmetrical - it is stronger in some directions than others. One can also say that, averaged over all directions, the tidal gravity increases when an object moves. Some authors have used the total velocity imparted by a "flyby" rather than tidal forces to gain an indirect measure of the increase in gravitational "effective mass" of relativistically moving objects (Olson & Guarino 1985) While there is unfortunately no single definitive way to interpret the space-time curvature caused by a moving mass as a Newtonian force, one can definitely say that the motion of the molecules in a hot object increases the mass of that object. Note that in General Relativity, gravity is caused not by mass, but by the stress–energy tensor. Thus, saying that a moving particle has "more gravity" does not imply that the particle has "more mass". It only implies that the moving particle has "more energy"."

17. anonymous

Incidentally, I've never seen it written, but I searched it and it should actually be "in the same vein" instead of 'vain.'

18. anonymous

I think, the mass will decrease as you go faster..and so that the weight.. Ta Da... now don't ask me how... :P

19. anonymous

W=m*g So no,since the mass of the object NEVER changes and the gravitation pull stays the same (~10) the weight does not change

20. anonymous

@irishboy123 @shigalntern Do you think this is right? ^ Lol