# Recent Activity

1. ### fishspawned replied to the thread B Franklin bell question.

yup - that's what i thought. good point on the assumed neutrality of the ball too.

Sep 22, 2018 at 9:18 PM
2. ### bhobba liked Auto-Didact's post in the thread A Hardy's approach to quantum gravity and QM interpretation.

@bhobba I agree that the modern desire for mathematical rigor is not necessarily warranted or even actually all that useful in...

Sep 22, 2018 at 9:17 PM
3. ### Drakkith replied to the thread I How a solid body emits a lower frequency photon than absorbed.

No, not necessarily. Once a molecule has absorbed energy and started vibrating, rotating, etc, it can often get rid of that energy in a...

Sep 22, 2018 at 9:09 PM
4. ### Drakkith replied to the thread Splinters stuck in skin.

In most cases, no. The natural shedding process of the skin would eventually push it outwards until it is shed. However if they have...

Sep 22, 2018 at 9:06 PM
5. idea2000 posted a new thread.

### new account, can't post or verify email

Hi, My cousin just registered a new account, but he can't post a new thread, as the button is missing and he also can't verify his...

#### Forum: General Discussion

Sep 22, 2018 at 8:57 PM
6. ### CharlieCW replied to the thread Coherent states for Klein-Gordon field.

Thank you. I see, then the idea was to take differently the labels, so I'm saving this general idea for future problems. Indeed, I...

Sep 22, 2018 at 8:56 PM
7. ### Eclair_de_XII replied to the thread What is the probability of getting r heads before s tails?.

Okay, now I need to find out what $E|T_1$ is. I have a strong suspicion that $E|T_1=(\bigcap_{i=2}^{s} T_i)^c\cup$ and something...

Sep 22, 2018 at 8:55 PM
8. ### Dale liked Vanadium 50's post in the thread I How was electron energy measured?.

Given the OP's, um, questioning attitude towards relativity, it's not 100% clear what will satisfy him. I think the crux of the...

Sep 22, 2018 at 8:50 PM
9. ### Mister T replied to the thread I 2 definitions for voltage, how are they equivalent?.

$$V_a - V_b =\int_{a}^{b} \textbf{E} \cdot d\textbf{s}$$ and, $$V_b - V_a = - \int_{a}^{b} \textbf{E} \cdot d\textbf{s}$$ But they...

Sep 22, 2018 at 8:49 PM
10. ### doggydan42 replied to the thread Compton Scattering and Recoil Velocity.

Are you referring to the missing factor of 2 in the equation for $\lambda_f$? If so, when. I plugged in the values in the next...

Sep 22, 2018 at 8:41 PM
11. ### nrqed replied to the thread Compton Scattering and Recoil Velocity.

The mistake is right there.

Sep 22, 2018 at 8:36 PM
12. ### nrqed replied to the thread Muon decay rate.

This last expression cannot be right, since the dimensions in the delta function do not match ($u^2$ has the dimensions of an energy...

Sep 22, 2018 at 8:34 PM
13. ### Chare replied to the thread I Derivation of Rindler metric.

So is this like being on an accelerating bus. You feel a force in your reference frame but at least in typical classical physics the...

Sep 22, 2018 at 8:31 PM
14. ### nrqed replied to the thread Velocity calculations in SR.

The question is a bit confused. If I understand correctly, you are considering two objects dropped from a certain initial height and...

Sep 22, 2018 at 8:28 PM
15. kiki_danc posted a new thread.

### Splinters stuck in skin

If you have fillings (such as from iron dusts or carbon fiber) stuck in your skin? would it eventually join with your blood flow? What...

#### Forum: Biology and Medical

Sep 22, 2018 at 8:18 PM