# AlphaGeek

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1. ## Kerbal Physics for a Cookie

You are a Kerbal physicist for Kow Jumped Over the Mun, a company that excels in anything spacey or astronaut-y. Your co-worker, Kirby McKerbin, is arguing with the desk clerk Moony Muni. Because you clearly have nothing better to do until next launch, you decide to listen in. Kirby is absolutely convinced that if he were to oscillate a pendulum on Kerbin, move it to Mun, and repeat the same occilation, the period of the pendulum on Mun would be roughly 3.5 times that of the period of the pendulum on Kerbin. The clerk argues that the period on mun would be 2.5 times that of the period on Kerbin. Settle this mess! Who's right and who should be working at McKerbals (Kerbin's largest fast food restaurant chain)? ****HINT: the surface gravity of Mun and Kerbin can be found on this site >> http://wiki.kerbalspaceprogram.com ****** ...Scary but true. They can't tell the females from the males in our species, either.
2. ## MOAr BrAin FyzicKs

Ever wonder why studying hard or taking multiple AP tests in a row makes you exhausted, or even hungry? This is because when you think, your brain has to work hard to send "messages" through the neurons to different parts of the brain and body. Cellular respiration turns your food (glucose) into adenoside triphosphate, or ATP. This is the molecule that many body functions require to do work, such as facilitated diffusion, muscle movement, and yep, you guessed it-- thinking. The sodium ion pump that creates a gradient in the nerve cell interior allows for the inside of the cell to become positive. The combination of the ATP- using sodium ion gradient and the two diffusion- using potassion and sodium channels allows for the neuron to send an electric pulse down the axon. At the end of the cell, called the transmitter, the pulse allows ligands (or signal molecules) to continue the message to the next brain cell, which will send another signal until the message reaches its intended destination. ...Scientific evidence as to why proctors should let us return to our bags for food. Physics says we need it to think! Post below with your favorite brain food! Mine is a chocolate chip cliff bar, and I know a certain math geek's is a buffalo chicken wrap Happy post-APs, everyone! --Alpha Geek
3. ## KSP - Kailzah LLP

Pre-Launch Design Release ****NOTICE: We ditched our old goal of making an unmanned orbit because a spacestation in orbit is cooler****** Team Name: Kailzah Available Funds: 37426 Vehicle Name: October Sky II Vehicle Parts List and Cost: Aerodynamic Nose (680x1), Ox. 4 Photo P. (300x2), Probodoyne OKTO2 (230x1), adv. SAS mod. (1,100x1), RCS Thruster (450x3), RCS Fuel Tank FL-R25 (800x1), Inline Clamp O Tron (700x1), TR-18A Stack Decoupler (600x3), FL-T400 Fuel Tank (850x1), FL-T800 Fuel Tank (1,600x1), liquid fuel engine (475x1), Rockomax Adapter (50x1), Rockomax Jumbo 64 Fuel Tank (12500x1), Mainsaid Liquid Engine (850x1) Design Goals: We used a rather large engine in combination with two connected smaller fuel tanks and three decouplers to ensure that October Sky II makes it into orbit. Launch Goal: With this launch, we hope to put a space station into orbit around Kirbin. We hope to learn how to make a proper orbit around Kerbin (this being our first official launch). Also, we hope to use this space station in the future with our further launches. Pilot Plan: 1. Turn on SAS and go full throttle 2.) During overheat, turn down throttle to 75% 3.) Decouple and loose the first fuel tank when fuel is low/out 4.) Go full throttle and enguage RCS 5.) Turn on propgade 6.) After exiting the atmosphere, cut engine 7.) Examine orbital position & approach apopolis 8.) full throttle & widen untill path is suitable for orbit Illustrations: Safety Rep:
4. ## KSP - Kailzah LLP

Pre-Launch Design Release ****NOTICE: We ditched our old goal of making an unmanned orbit because a spacestation in orbit is cooler****** Team Name: Kailzah Available Funds: 37426 Vehicle Name: October Sky II Vehicle Parts List and Cost: Aerodynamic Nose (680x1), Ox. 4 Photo P. (300x2), Probodoyne OKTO2 (230x1), adv. SAS mod. (1,100x1), RCS Thruster (450x3), RCS Fuel Tank FL-R25 (800x1), Inline Clamp O Tron (700x1), TR-18A Stack Decoupler (600x3), FL-T400 Fuel Tank (850x1), FL-T800 Fuel Tank (1,600x1), liquid fuel engine (475x1), Rockomax Adapter (50x1), Rockomax Jumbo 64 Fuel Tank (12500x1), Mainsaid Liquid Engine (850x1) Design Goals: We used a rather large engine in combination with two connected smaller fuel tanks and three decouplers to ensure that October Sky II makes it into orbit. Launch Goal: With this launch, we hope to put a space station into orbit around Kirbin. We hope to learn how to make a proper orbit around Kerbin (this being our first official launch). Also, we hope to use this space station in the future with our further launches. Pilot Plan: 1. Turn on SAS and go full throttle 2.) During overheat, turn down throttle to 75% 3.) Decouple and loose the first fuel tank when fuel is low/out 4.) Illustrations: Any other photographs or illustrations to help communicate your plan. Safety Rep: Which safety representative is this plan being submitted to? Note that once this is posted, you may not launch until you have written confirmation in the form of a reply to this post from the safety rep that your plan is complete, sufficient, and has addressed risks and concerns appropriately.
5. ## The bees Eye view

That's so cool! Bees are absolutely amazing. Their communication and "hive mentality" is equally remarkable. Have you watched the NOVA special on waggle dances? http://www.pbs.org/wgbh/nova/nature/waggle-dance.html
6. ## Coat-hanger Bubbles Experiment

Yay coat hanger! I hope you don't mind, I posted on this topic too but cited your blogpost in it. Nice work here
7. ## Coat hanger solenoid

...Hi guys, my pictures came out as words. How can I make them into pictures again? D:
8. ## Coat hanger solenoid

As Goalkeeper0 and Mr. Fullerton suggested, I decided to give the soap-and-water approach to understanding flux a shot. If you'd like to try this experiment but can't find one of those ancient metal coat hangers, here's a different approach: >>>Credit to Goalkeeper0<<< I bent a coat hanger into a solenoid with 5(ish) loops and filled the dish basin in our sink with soapy water. I'm not sure if it's because here wasn't enough soap in the water or a different factor, but the darn soap layer kept popping before I could pull the hanger completely out of the basin. Here's low quality evidence of my findings; ...Again, you really can't see much in the picture. I recommend doing the experiment yourself. To give you a better idea of what the soap spiral looked like, it resembled the shape of fusilli pasta. EX: Yum. Love the stuff Again, this shape is meant to demonstrate how the number of N turns in a solenoid effect the flux. The more loops in the coat hanger, the more bubble-surface there is in our solenoid. This helps reinforce the equation Mag. Flux = BANcos, with B= Mag. field, A= area and N= number of turns in the solenoid. --Alphageek
9. ## How to put eqns/fancy symbols into your blog

Do you find your blogs boring, drab and in need of fanciness? Do you think that int(x^2) is an acceptable substitute for ? Because the APlusphysics site has undergone improvements, I think that our blogs' equation quality should improve as well. ;D A little birdie (Mr. Fullerton) told me about this great tool called a latex editor. One site to go to is http://www.codecogs.com/latex/eqneditor.php , which you don't have to download and it's not blocked by the school. It's a site where you can choose the symbols that you want in an equation, like sigma or pi, and it spits back a code. When you paste that code into your blog post, put $$before it and$$ after it, then preview the blog, the symbol you chose will be in its place. I had to put the information above into the code box or the computer would've read it as part of a code. For example, if I choose the pi button and the latex editor spits back CHERRY, I would write [ tex] CHERRY [ /tex] and the symbol for pi would come up. (the code is actually \pi, so if I surround that with $$and$$ it looks like: $$/pi$$ I hope thats helpful! If you have any questions, Mr. Fullerton or I would be glad to help
10. ## Physics Equations: E&M

Part 2 of the equation posts: E&M. Again, if you see any mistakes or have a few equations to add, make sure to utilize the comment section! I'll add it in right away. Electrostatics E= Fe/q = kq/r λ = Q/L ρ = Q/V σ = Q/A Electric potential Ue = kq1q2/r F = -dU/dl V = k ∑ qi/ri = W/q ∆V= Vb - Va = ∫ab E dl = ∆U/q Gauss's Law: Conductors Esurface= Vinside = Einside = Capacitor C=Q/V = Uc = Ue = field energy density = Energy = V/d C= w/ = Dielectric constant Circuits I = I = V/R I = NqVdA = NeVdA Current density (J) = NqVd = I/A charging up: w = I2V charging down: U = CV2 = RC 5 = 99% charged/discharged Resistance R= E= P=IV E= J W= qv Series Circuit Ceq = I= constant V=IR Req= R1+R2+... Q=CV Parallel Circuit Ceq = C1 + C2 + ... I = V/R V= constant Q=CV Batteries: Videal = V = mf = VT V with resistance = Iri = VT Pbattery = W/t = = I Pexternal resistor = I2R Pinternal resistor = I2ri Magnetism Gauss's Law: dA = O Amphere's Law: Ipen ...for a wire of radius R, B = Biot-Savart law: dB = (dl X r) ...for a loop of wire, B = Faraday's Law: = = solenoid: B = toroid: B = Mag. moment () =NIA =NIR2 Mag. torque= ...sorry that took so long to post up, jeez that code takes a while to type up ^-^ Feel free to add/correct in the comments section!
11. ## Physics Equations: Mechanics

Having trouble on the 4 minute drill? Need to consolidate your thoughts for the Mechanics part of the AP-C exam? Have no fear! I've sifted through my notes to find a good portion of the mechanics equations. If you find anything missing/incorrect, PLEASE give feedback in the comments section! I'll edit the changes in ASAP. Thank you MECHANICS Vectors etc. A B = lAl lBl cos Ө A x B = - (B x A) lA x Bl = lAl lBl sin Ө Kinematics V= Vo+ at Δx = Vo t + (1/2) a t2 V2 = Vo2 +2aΔx Δx = ∫ v(t) dt Δv= ∫ a(t) dt Vavg = Δx/Δt = (Xf - Xo)/(tf - to) V= dx/dt a= dv/dt UCM/gravitation Fc = mv2/ r ac = v2/r = w2/r Fg= GMm/r2 Ug= -GMm/r Rotational Motion S= Өr v= wr a= αr w= ΔӨ/Δt ac= w2r Vlinear = 2πr/t parallel axis theorem: I = Io +md2 KEroll= (1/2)Icmw2 + (1/2)mv2 Angular momentum (L) = r x p = mvrsinӨ = mwr2sinӨ dL/dt = Torque L= w I K= (1/2) I w2 Moment of Inertia I = Σmi(ri)2 = ∫r2dm Isolid disk = (1/2) mR2 (also works for a cylinder about its axis) Ihoop = mR2 Isolid sphere = (2/5)mR2 Ihollow sphere = (2/3)mR2 Irod about center = (1/12)mR2 Irod about end = (1/3)ml2 Torque (T) x >> Ө v >> w a >> α m >> I F >> T ΣF = ma >> ΣT = Iα T = rxF = rFsinӨ T = (Radius)(tension) Center of Mass rcm = Σmr/Σm = ∫r dm / Σm Xcm = (m1x1 + m2x2)/ (m1+m2) Drag force Fd = bv = cv2 VT = mg/b V = VT(1 - e(-b/m)t)= (mg/b)(1 - e(-b/m)t) Friction Ff= μ Fn ...As to not get long and confusing, I'll make another blog post with all of the Electricity & Magnetism equations that I have in it. Check that post out, too! --Alpha Geek
12. ## Hitler Reacts to the AP Physics C: Mechanics Exam

Hahahahaha, that was hilarious! I feel similarly about physics with no numbers ;P Nice post.. No worries about swearing, it's not like the videos show up on school computers anyway. ^^;
13. ## The Physics of Memorizing Magnetism Equations

Thankyouthankyouthankyou! --Good luck tomorrow everyone! I've found the book is pretty helpful for last minute clarification, so if anyone else needs help that's where to go
14. ## THe Physics of Blog Posts (Part II)

Quote of the year right there ;D Right up there with "Hey -- Heeeeeeey!" and "Zombie cookie"
15. ## My Cookie Problem

COPYRIGHT INFRINGEMENT. I'm taking you to court, Stack. Better find a lawyer
16. ## i was wondering...

Cheers to that, although considering the grader it might count as a negative blog post ;P I wonder if Mr. Fullerton really has than many tatoos
17. ## "How Fast Would the Earth Have to Spin to Fling People Off?"

Haha, good thing! You had me worried for a second there Nice post!
18. ## Physics of a Tsunami

Wow, love the gif! A quality visual for a quality blog post

20. ## The physics of roof trusses

Yay truss XD It came out great!
21. ## Military Physics

I'm not sure if this is cliche, but I saw this on television once and thought it deserved a physics-rundown (It was a future weapons episode). This bulletproof vest, called "Dragon Skin," is manufactured by Pinnacle Armor. It was designed for military use, though it failed Army inspection (the heat test: the vest was heated up to 170 degrees F and was shot at afterward. The clay material backing couldn't withstand the heat, and the design lost its overlapping shape. The integrity of the vest was lost, thus the vest was deemed unsafe). HOWEVER, despite this subtle detail, the vest's design is truely ingenious. The overlapping-disk design distributes the impact of a bullet to multiple plates, whereas on a single plated vest the force is absorbed by only one plate. On the specific epistode of Future weapons where this armor is featured, it withstood a number of tests, including shots from an AK-47 and an M67 grenade. In the case of the grenade, even though the vest itself was ripped to shreds, the armor itself was still intact. The vest was officially declared to provide "level 3 protection," which means that it can protect agains 9.6 g bullets traveling at 847 m/s, give or take a few m/s. ...For those of you with an interest in physics and no occupation to apply it to, the military is looking for creativity --Alpha Geek
22. ## Electromagnetic Rail Gun

Yikes, that's a scary new toy. Physics is dangerous :black_eyed:
23. ## Physics for a cookie: Toy story problem

Hi everybody! I haven't done a cookie problem in a while, so here it goes! The problem is related to the current unit. First correct answer gets a cookie. I think Charlie is the only one who answers these things, but I enjoy writing them and he likes cookies, so... It all works out :glee: Slinky the dog is bored (since Andy is off at college and all), so he decides to watch Walter Lewin's video Lecture 15. Slink thinks the solenoid example is really cool and decides to try it out himself. If he hooks his middle into a circuit of 1A and stands with his front feet .5 m away from his back feet, what is the magnetic field inside of Slinky? Note: Slinky's center is composed of 100 turns, and each turn is uniformly spaced. I love Disney! Bonus question: What is the name of the arcade in Toy Story? Have fun! --Alpha Geek
24. ## Electricity in the Brain

More electricity-themed blog posts! Neurons are cells in the nervous system. This cell transfers information via chemical and electrical signals. The long, stem-like part of a nerve cell is called the axon. In the human body, the axons that run from your spinal chord to your feet can be over a meter long. Electrical pulses are transferred through the axon down to the neurotransmitter molecules. The membrane potential of the average neuron cell is between -60 and -80 mV when the cell is not transmitting signals. The electrical signal is converted into a chemical one once it reaches the synapse. The synaptic vesicles (containing ligands called neurotransmitters) release small molecules, which flow over to the receptor molecules on the adjacent nerve cell, and the message travels through a net of these cells until it reaches its destination. Some interesting facts about the nervous systems of various species: -- The electric eel is equip with 8,400 neurons, which can potentially crank out a painful 600 V. -- It is estimated that the human brain contains roughly 100 billion nerve cells. -- All animals except sponges have a type of nervous system. -- The contraction and expansion of a Hydra is controlled by a nerve net, a web-like system of neurons that span the organism's body. Shocking, eh? :einstein) --Alpha Geek
25. ## Liquid Magnets?

0.0 That's so cool!
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