“They saw their injured country's woe;
The flaming town, the wasted field;
Then rushed to meet the insulting foe;
They took the spear, - but left the shield.”
―Philip Freneau
.
And by a prudent flight and cunning save A life which valour could not, from the grave. A better buckler I can soon regain, But who can get another life again?
Archilochus
Sadly the premise that mass increases with increasing speed is actually wrong. Speed cannot alter the internal structure of a massive body.
Instead we use the concept of relativistic momentum.
See:
It is not good to introduce the concept of the mass {\displaystyle M=m/{\sqrt {1-v^{2}/c^{2}}}} M = m/\sqrt{1 - v^2/c^2} of a moving body for which no clear definition can be given. It is better to introduce no other mass concept than the ’rest mass’ m. Instead of introducing M it is better to mention the expression for the momentum and energy of a body in motion.
— Albert Einstein in letter to Lincoln Barnett, 19 June 1948 (quote from L.B. Okun (1989)
From wikipedia.
The increase in momentum (with increasing speed) is the consequence of changes in geometry (space time)
I am woefully ignorant of the higher laws and theories of Science, but isn't it true that the faster an object moves the greater force it exerts upon impact?
After all, a bullet is quite harmless util it's fired, nest-ce-pas?
Unless, of course, one would be foolish enough to swallow it, which would likely cause harm of quite another variety.
14 comments:
Life is made of mysteries ––
___ myriad mysteries ––
Layers upon layers of baffling ––
___ unfathomable ––
______ impenetrable ––
_________ mysteries.
Thrilling –– chilling ––
___ unimaginable ––
______ seductive ––
_________ taunting –––
____________ haunting ––
_______________ mysteries.
~ Freethinke
Indeed!
...but just to complicate (or clarify) things...
Sadly the premise that mass increases with increasing speed is actually wrong. Speed cannot alter the internal structure of a massive body.
Instead we use the concept of relativistic momentum.
See:
It is not good to introduce the concept of the mass {\displaystyle M=m/{\sqrt {1-v^{2}/c^{2}}}} M = m/\sqrt{1 - v^2/c^2} of a moving body for which no clear definition can be given. It is better to introduce no other mass concept than the ’rest mass’ m. Instead of introducing M it is better to mention the expression for the momentum and energy of a body in motion.
— Albert Einstein in letter to Lincoln Barnett, 19 June 1948 (quote from L.B. Okun (1989)
From wikipedia.
The increase in momentum (with increasing speed) is the consequence of changes in geometry (space time)
https://en.wikipedia.org/wiki/Mass_in_special_relativity#Controversy
Thanks for the supplemental info! Interesting ways to imagine, from the master imagineer himself!
Welcome.
The 'concept of relativistic mass' is fascinating to laymen. Unfortunately it doesn't really exist!
It's all about momentum and (kinetic) energy...
I am woefully ignorant of the higher laws and theories of Science, but isn't it true that the faster an object moves the greater force it exerts upon impact?
After all, a bullet is quite harmless util it's fired, nest-ce-pas?
Unless, of course, one would be foolish enough to swallow it, which would likely cause harm of quite another variety.
the faster an object moves the greater force it exerts upon impact?
...by the square of the velocity.
e=mv^2
So you're saying I am correct?
Jus tseems like Common Sense to me.
the faster an object moves the greater force it exerts upon impact?
...by the square of the velocity.
e=mv^2
Unfortunately it is much more complicated than that. Firstly, the non-relativistic kinetic energy Ek is given by:
Ek = 1/2 mv^2
But how much force is generated upon impact doesn't depend on Ek ONLY.
Imagine two objects of the same mass m and traveling at the same velocity v. Hence they both have the same Ek.
Now imagine Object 1 to be something hard and unyielding like a bullet and Object 2 a very fluffy, spongy toy.
Both now hit a wall in identical circumstance. Which will produce the highest impact force?
There's a reason why they put bales of hay around racetracks, instead of blocks of granite!
In the case of collisions, we use the concept ofImpuls, rather than force.
These things are all related, yet distinctly different.
Indeed. Thanks for the finer distinctions!
Piacere.
Post a Comment