# Aziraphale

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 Feb 12 comment Two body problem with given start positions and velocities If your time step is small enough, you can loop over all bodies and calculate the total acceleration on each of them (component-wise). Multiply with the time step to get the change of velocity and from that you get the change of location. That way, you implicitly have covered all 2-body problems. Jan 19 comment Why are forces independent from the frame of reference? No. It is the other way round: We derive the last equation and from that we conclude that $K'$ is an inertial reference frame. ma' is the sum of all forces in K'. There are no other forces (Eq. 1). This is expressed in the equation SUM(F')=ma'. Not more and not less. Jan 19 comment Why are forces independent from the frame of reference? Equation 1 says it all. Accelerations/Forces in both reference frames are the same. This is because $\underline{w}$ is constant. Can you explain what exactly is not clear to you? Dec 18 awarded Citizen Patrol Dec 18 comment Does irregular reflection form images? I think your teacher is right, because the reflection is irregular. Irregular means not organised in any way. Dec 17 comment How far can light go? After my answer including this cartoon has been upvoted, downvoted, flagged and deleted, I would like to share this with you as a comment. Merry christmas to all of you. Dec 15 comment How far can light go? Does this mean that individual photons lose energy? Or is it rather the decreasing number of photons that reach us, resulting in less energetic radiation? Dec 8 comment Atmosphere model I guess you need mesoscale forecasts? Why are you trying to make your own model? This will take months and years. Some model output can be obtained for free (e.g. GFS). Use that data to feed your glider software. Dec 3 comment Introducing angular momentum for the first time to a class Are you asking how to introduce the pseudo vector or how to introduce the concept itself? Dec 2 comment Does anyone know the mechanism behind this double helix cloud formation? It is difficult to judge the height at which this phenomenon occured. From the article mdornfe1 mentioned, I would guess that some obstacle in the air can trigger this slowly swirling motion. I must admit that I didn't read the article carefully enough, but the Reynolds numbers and stability mentioned there indicate that a scaling from wing tip swirls to some 100 m could really work. Maybe big platforms of television towers (imagine the bis ball of the berlin tower) can induce this double helix in just the right amount of wind speed and atmospheric stability. Dec 2 awarded Informed Dec 1 answered On what basis is it said that lightning does not strike the same place twice? Aug 27 comment Calculating new temperature of an object when air temperature changes However, with a controlled experiment you can estimate the conductivity: Start with a known air and object temperature, respectively. Then take readings of both at regular intervals. The average change in the temperature difference divided by the time interval yields the conductivity. With Fourier's law you can predict the object's temperature. Aug 27 comment How do you add temperatures? As long as you stick with one unit, you can interpolate as usual. The average of 400K and 500K is (400+500)/2. Your problem is probably to apply a proper interpolation method. Your 828 degrees are outside of the key value data set, so you need to extrapolate. Maybe you can change the question towards this direction? Aug 27 comment Why isn't jumping against a wall an elastic collision? Maybe there is something wrong with the wall. yhgdfg should be more specific about the setup of the experiment. How often did he jump against the wall? Which body parts hit it first? I only want to avoid closing of the question due to insufficient effort. Aug 26 comment Increase contrast on the image taken by CCD camera HDR means that you artificially increase the dynamic range (i.e. the range between over-exposed and under-exposed areas of an image) by combining images taken with different exposure times. Bright areas (e.g. sky, clouds) are well displayed on images with a short exposure time, whereas shadowy areas need longer exposure times to reveal details. The combination will show ALL details. So, if your pattern has darker and brighter areas you can simulate a higher sensitivity with low noise. Aug 26 comment Relationship of multiple particles under collision You assume that particle 1 reverses its direction after the first collision. This is wrong. Example: A=0.1, B=100. Aug 26 comment Relationship of multiple particles under collision I was trying to direct him towards am more focussed question in this homework. momentum = mass x velocity should be helpful. Aug 26 comment Relationship of multiple particles under collision Have you tried some scenarios? What if A>B, A