Question

water on Mars
https://www.youtube.com/watch?v=ZTlzn1Cce6o

Answer 1

She is our serious hope of future astronomy. I can smell..

Answer 2

ganeshie

Answer 3

if a photo collides with a particle at rest and the rest mass is absorbed can i use linear momentum to find velocity @ganeshie8

Answer 4

idk why i ask you this even though you haven't done any particle/quantum/relativity physics

Answer 5

or maybe you have idkkk

Answer 6

momentum conservation woo

Answer 7

conservation of linear momentum works no matter what the velocities are

Answer 8

that is one law that works at speeds comparable to light speed too

Answer 9

yeah but we have to apply a lorentz factor i think

Answer 10

ooh yeah http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/relmom.html

Answer 11

i don't know special relativity, but i know that linear momemtum doesn't care about it

it must be conserved irrespective of the speeds

Answer 12

Actually you do get different answers close to the speed of light

Answer 13

You could try doing non - relativistic calculations and try yourself if you're interested, cool stuff

Answer 14

are you saying linear momentum is not conserved at higher speeds ?

Answer 15

how sure are you about that statement ?

Answer 16

i don't know special relativit, so i can't do any calculations

Answer 17

but from classical mechanics i do know that linear momentum of a system must stay same even at near light speeds

Answer 18

Naw that's wrong, I could show but I think you need to have some understanding of relativity as everything will be in relativistic terms kind of. We actually just assume that in mechanics, it's pretty cool because there's a whole "einstein dynamics" to it lol it's not arbitrary at all either . Because I just did calculations for speeds close to light and mechanics was off by a pretty large factor compared to the relativistic speed XD

Answer 19

are you really saying linear momentum is not conserved at higher speeds ?

Answer 20

Nooooo, it is conserved

Answer 21

I guess I shouldn't have said it's wrong, just needs to be tweaked a bit, but I'm still learning this stuff so I could be wrong lolol

Answer 22

Mechanics is not wrong, but incomplete

Answer 23

Actually yes, it's not conserved with classical mechanics!

Answer 24

Because in one inertial frame momentum is conserved but if we use the transformations for another coordinate system momentum is not conserved ahh!

Answer 25

i can't make much sense of those relativity arguments...

Answer 26

Haha, yeah it's sort of weird, did you check out that book I gave you? I think you would get some of it if you read chapter 1 and 2 as you will understand all the reference frame stuff!

Answer 27

my textbook says that linear momentum is conserved at light speeds(special relativity) and at sub micron lengths (quantum mechanics)

Answer 28

so i thought we will not have any issues with when a photon strikes an atom.

to my classical brain, the linear momentum of photon+atom system must be same before and after the collision

Answer 29

Must be generalized, I don't know even I get confused by this at times

Answer 30

Photons are fascinating, it's a whole new physics when you go into that as it will have to do with scattering, the momentum of a photon is \[p = \frac{ E }{ c } = \frac{ h }{ \lambda }\] it's a whole new ball game

Answer 31

It has no mass xD!

Answer 32

rest mass*

Answer 33

this is from halliday 11th chapter

Answer 34

Well my book is pretty old let me check modern physics because I don't really know what to think of that right now

Answer 35

http://puu.sh/lnpwD/8c638c595a.png

Answer 36

So kind of like what I said

Answer 37

Interesting... but i can't really make any sense of that... i lack the relativity juice

Answer 38

Stick to this book, it's very good!

Answer 39

You can see it has a whole section dedicated to modern physics

Answer 40

Though it's not deriving everything it gives a good sense

Answer 41

i want to review electromagnetism first, then do quantum mechanics

Answer 42

GR is far away...

Answer 43

I need to review that as well, I've only done algebraic E&M

Answer 44

Yeah lol

Answer 45

I'm going to go over this whole book sometime next year so it will be fun and I'll have lots of questions :P

Answer 46

Is that same as Young and Freedman university book ?

Answer 47

Yup, my baby

Answer 48

The print screen one