Test Driving a Car Virtually
I played around in another thread with mathematically determining where a car should be time wise on 1/4 mile run. I had a chance to drive this car myself giving me more information than you normally...
View ArticleCoverting Simple Harmonic Motion Equation to a Rotational Model
Hi I am using Simple Harmonic Motion in a Matlab/Simulink model. Instead of using a motion for a simple pendulum, I decided to use a spring with a mass. The reasons for this is because my example is...
View ArticleDesign of a Solar Drone
Recently, Facebook suggested solar powered drones could be used to provide internet coverage in remote areas and they would basically act as low altitude 'geostationary' satellites. The current...
View ArticleOptics: Why not polished surfaces reflect less than polished ones?
Hello, I would like to ask why, when a surface is not polished, it reflects less. I understand that when the surface is not polished, microscopically it presents a lot of irregularities so that when...
View ArticleConstant momentum of an accelerated body
Momentum of a body can be constant while it accelerates? I mean if velocity increases while mass decreases proportional. And if is true, what force produces acceleration?
View ArticleUnderstanding the Jacobian
Hello, I'm trying to make my own physics engine. I've already made one with momentum and an very easy collision solver, but it was creepy and full of bugs because I solved the contacts one after...
View ArticleFluid stress tensor in spherical coordinates
Hi everyone. I have a question on how to compute the fluid stress tensor in spherical polar coordinates. I actually just want a check on my method to see if it is correct. The stress tensor in...
View ArticleWhen Two Rocks Collide
(This is not a homework problem, but is just something I'm curious about.) If two rocks with different momentum collide, how much "damage" will the rocks receive as a function of their momentums? For...
View ArticleAngular velocity of an object with radius and time
Greetings, I fell upon a certain question and it seemed that no matter what I did I was unable to solve it. I wished to know how if given a radius of 0.6m and the time for one revolution: 0.3s, to find...
View ArticleRotation dynamics, dealing with impulse and oscillation
A homogene rod with length "l" is placed vertically, and a nail is stabbed on the top of the rod (now the rod has an axis). And then an impulse is given on the rod with the separation between the...
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How force works on two strings connected by a mass
So if I slowly pull the A string first B string will tear apart... Cause the A string will expand and it will pull the mass and B string... So B string will reach its breaking weight before A... Cause...
View Articlenavier-stokes order of magnitude
hey pf! i have a quick question with order of magnitudes, specifically relating to navier-stokes equations. when considering the pressure term of the x-momentum we have that ##-\frac{\partial...
View ArticleElectric AC Generator
Hi! I have been studying AC generators. I am confused about why there is no current when the armature is perpendicular to the magnetic field (when it is vertical). Also, what is the purpose of the...
View ArticleTime to Cook A Turkey
According to this website, there is an equation obtained empirically to obtain the amount of time it takes to cook a Turkey: t = W(2/3)/1.5 Is there any theory to support such a relation? Yes, the...
View ArticleApproximate inductance of a filamentary circular current loop
Hello everyone, I want to have a simple example of an inductance calculation. The magnetic field normal to a filamentary circular current loop is not constant over the circle but if we approximate the...
View ArticleChange in Entropy for Irreversible Processes
I was following along in my Thermodynamic textbook and began playing with some definitions. In the following formulation, I somehow managed to prove (obviously incorrectly) that [itex]dq = TdS[/itex]...
View Articlewet vapor through a nozzle, entropy of a wet fluid
I have come up with an idea for a new simple jet engine. It will use an injector to "pump" in the fuel, in order to reduce the number of parts and wear on movable parts. However depending on the...
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Given localized moving charge density ρ(X,t), determine electric and m
Suppose we have two co-linear strings under tension, attached far away, and with propagation speed v. Let the strings have equal and opposite linear charge densities. In each hand you hold an end of a...
View ArticleLagrangian/Hamiltonian problems and find the position
Hi, does somebody know a good website with many exercises about Lagrangian/Hamiltonian mechanics? And I mean problems with physical system and no mambo jambo around it. A list of like 30 problems with...
View ArticleMomentum and energy of rebounding balls
Greetings, I was thinking about bouncing a tennis ball against a wall and how its momentum and kinetic energy would change. I asked a friend of mine and he answered that the ball would transfer more...
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