147,053 reputation
13250412
bio website ratsauce.co.uk
location Chester, United Kingdom
age 54
visits member for 4 years, 7 months
seen 17 hours ago

Semi retired old time computer nerd who started programming on a Commodore Pet.

Since I'm also active in the Physics forum I should add that I started as a theoretical chemist, moved into solid state photochemistry and finally worked in industry as a colloid scientist. I only became a full time computer nerd in 1997.


Aug
20
comment Would opening a car door at high speed change the path of the car?
Hi Dopapp. This is a site for questions about physics. So you might for example want to ask about the equations that describe aerodynamic drag. But as it stands your question is not a good fit for this site.
Aug
20
comment Is there any reason for principle of least action to be true?
The question Why the Principle of Least Action? is also related.
Aug
20
comment Is there any reason for principle of least action to be true?
possible duplicate of How do I show that there exists variational/action principle for a given classical system?
Aug
20
comment Why is spacetime curved by mass but not charge?
@InderGill: we can. See Can all fundamental forces be fictitious forces?
Aug
19
comment On what basis do we trust Conservation of Energy?
@RBarryYoung: the technical meaning is that the action exhibits time shift symmetry. As a simplification, you can think of this as saying that the laws of physics don't change with time.
Aug
19
comment How can a phosphorous ion dope silicon when it is already ionized?
@JonCuster: that should be an answer.
Aug
19
comment Anti-centrifugal force?
possible duplicate of What forces are at work causing sand to migrate to the centre of a spinning bucket of water?
Aug
19
comment Special relativity paradox
OK, but your question says: doing the calculations tells us the opposite. Can you explain how you arrived at this conclusion?
Aug
19
comment Special relativity paradox
Can you explain how doing the calculations tells us the opposite i.e. update your question to give the working that shows this?
Aug
19
comment Elitzur–Vaidman bomb tester value on Wikipedia
To get to $C$ the upper beam is reflected three times and the lower beam is reflect once, so their phases are the same. To get to $D$ the upper beam is reflected twice and the lower beam twice, so actually I get the same phase at $D$ as well. Hmm.
Aug
19
comment a point charge is kept at the centre of a metallic inducted spherical shell.then why the net induced charge on the sphere is zero?
If charge can neither flow onto or off the spherical shell the net charge cannot change.
Aug
19
comment How to calculate the work of the electrostatic forces in a parallel-plate capacitor?
Your initial assumption is wrong. The work is the work required to transfer the charge onto the plates against the EMF produced by the charge already on the plates. The result should be $\tfrac{1}{2}CV^2$. The plate separation remains constant.
Aug
18
comment Why we want to convert a voltmeter to an ammeter or vice versa?
Voltmeters are ammeters they determing the voltage by measuring the small current that passes through a known high resistance then calculating the voltage using $V = IR$.
Aug
18
comment Why we want to convert a voltmeter to an ammeter or vice versa?
I'm voting to close this question as off-topic because it's about electrical engineering and should be on the Electrical Engineering SE.
Aug
18
comment Why is raindrop spherical in shape?
possible duplicate of Why drops form spheres?
Aug
18
comment Time dilation and relativity paradox?
There is no way for the space-train and an observer 1 light year apart to synchronise their clocks, so none of the rest of your argument follows.
Aug
18
comment Forces acting in a system of a bar suspended by two rods
Hi and welcome to the Physics SE! Please note that this is not a homework help site. Please see this Meta post on asking homework questions and this Meta post for "check my work" problems.
Aug
18
comment Is there a proof that space expanding produces observers at all points that see what we see?
@Timaeus: your answer is quite correct. The metric is independant of $x$, $y$ and $z$, so it implies homogeneity. My point is that homogeneity was an assumption made when deriving the FLRW metric in the first place, so of course it implies homogeneity.
Aug
18
comment Impossibility of time travel due to energy conservation?
@pela: any even remotely sensible approach to time travel requires following a closed timelike trajectory. This is just a path through spacetime, so at any point you would be able to see where you were going and make sure you didn't miss your destination. When you talk about missing Earth I'd guess you're thinking of time travel as some form of discontinuous jump, but no time travel mechanism we know of works like that.
Aug
18
comment What is the wavelength of a hot metal when its temperature 400 C?
Actually I agreed with Daniel's comment and added the first line in response to it. I just didn't admit it :-)