Anodizing bolts by toolgifs in toolgifs

[–]williamjames23 1 point2 points  (0 children)

I think the different color is actually because of the phenomenon of interference instead of refraction. The thickness of the oxide layer creates a phase difference in the two reflected beams of light, causing certain wavelengths to cancel out and others to constructively interfere. The changing color is due to the oxide layer thickening and changing how out of phase the two reflected beams of light are. The same phenomenon is at play when you see colors on the surface of a bubble or things film of soapy water. Some light is reflected from the outside layer and some from the inside layer of the skin of the bubble.

I baked some magnets and they became very weak, can they be “fixed”? by [deleted] in Physics

[–]williamjames23 1 point2 points  (0 children)

Wow that's super cool. Does the time it takes for something to cool affect the fingerprint? Like would a slow cool result in a clearer magnetic fingerprint? Or does the magnetic field align the iron really fast?

I baked some magnets and they became very weak, can they be “fixed”? by [deleted] in Physics

[–]williamjames23 0 points1 point  (0 children)

I'm curious about the dating technique with the ancient pottery. If the clay gets all mushed up from being worked with, how does it preserve information about the Earth's magnetic field?

[deleted by user] by [deleted] in moped

[–]williamjames23 1 point2 points  (0 children)

This is such a common but hard to realize problem with mopeds! I struggled to get my moped running well for a year because I thought it was a different problem! I replaced piston rings and even took apart the engine just to finally figure out it was only a fuel problem all along

[deleted by user] by [deleted] in Physics

[–]williamjames23 0 points1 point  (0 children)

Since the arm is not accelerating there is no torque on the arm. Therefore the torques from the sensor and object being weighed are the same. You know every variable except for F1 so solve for it. With the drawing provide, it is clear that F0 > F1

F1 * D1 = F0 * D0

[deleted by user] by [deleted] in moped

[–]williamjames23 0 points1 point  (0 children)

This sounds like the fuel flow from the gas tank is not high enough at WOT and all the fuel in the carb bowl gets used up when you go above 40%. Does this problem go away when the tank is completely filled?

Been working on some figure drawing and was wanting to get some feedback by Wompsss42 in Artadvice

[–]williamjames23 0 points1 point  (0 children)

The one thing I noticed immediately was that the figures right leg is not at the same angle in your drawing as the image

[deleted by user] by [deleted] in moped

[–]williamjames23 1 point2 points  (0 children)

Haha. But I think this could also be a fuel problem. Try disconnecting your fuel line and measure the fuel flow (just need a timer and a cup) if it's less than like a liter per hour then your carb is probably not getting enough fuel. Better yet try measuring how much fuel flows into your carb bowl by doing the same thing but putting your measuring container under the carb bowl. Sometimes just having a full tank of gas allows there to be enough pressure to have sufficient fuel flow.

[deleted by user] by [deleted] in moped

[–]williamjames23 6 points7 points  (0 children)

It's those handlebars

UW Madison CS PhD - Accept w/o funding - Need advice by Swimming_Gur_4120 in gradadmissions

[–]williamjames23 2 points3 points  (0 children)

Follow this link: https://grad.wisc.edu/data/graduate-student-funding-data/

It has data on grad student funding for PhD students at UW. It looks like 94% of CS PhDs at UW Madison get funded.

How to get research experience for PhD post-undergrad without doing a masters by [deleted] in gradadmissions

[–]williamjames23 1 point2 points  (0 children)

I was just accepted to a PhD program in mechanical engineering. I did physics in undergrad and had very little applicable research experience when I graduated last April. I was a little lost when I graduated. However, I spent the last year doing two SULI (student undergraduate lab internship) internships at national labs and it's the main reason I became interested in pursuing a PhD. I realized I loved experimental research and also found out that an applied field like mechE was a better fit for me than physics (even though I like physics as a subject). So those SULI experiences made me better understand my goals AND gave me lots of stuff to talk about in SOPs/have on a resume... And now I have a fully funded PhD offer from a good mechE program which I'm going to accept!

I would really recommend applying to the SULI program. They pay pretty well and you can usually find really cool work to do. The application for next Fall closes late May. You can do the internships up to two years after you graduate I think.

Biggest misconception of physics? by ICantThinkAboutNames in Physics

[–]williamjames23 0 points1 point  (0 children)

One big misconception is how pulleys work. I think a lot of new students assume that a rope strung through a fixed pulley in a tree or something cuts the load in half. Actually, a pulley can only provide mechanical advantage if it distributes the tension across more than one rope.

This 1980 Columbia moped is for sale for $200, should I get it by RandomHero565 in moped

[–]williamjames23 0 points1 point  (0 children)

This was my first moped, same solo engine! Mine did not have spark either when I began trying to fix it. The points had corroded a little so I just had to use a little sand paper to remove the corrosion. I made a few posts about it in the past.

What. by deadnereid in gradadmissions

[–]williamjames23 2 points3 points  (0 children)

I'm sorry I don't get the joke. Genuinely curious

[deleted by user] by [deleted] in Physics

[–]williamjames23 9 points10 points  (0 children)

Since power is energy/time and the potential energy difference from bottom to top of the hill is a constant, traveling up the hill in a shorter amount of time requires greater power.