Body Definition and 1000 Threads

Why a free rigid body with mass m, when applied with an external force F, translates with center of mass and all particles of body having same linear acceleration = F/m, but it always rotates only about its center of mass, but not about some any other point on the body? And, thus if the line of...

For the rod and the two particles ##x_1## is not zero but we have:$$x_2=x_3=0$$ We start with inertia tensor of the rod: $$ I_{ij} = \int \lambda ( \delta _{ij} \sum_{k} x^2_k -x_i x_j ) dx_1$$ $$ \lambda = constant = M/L $$ Using above equations, we have: $$I_{11} = \dfrac M L \int ( x^2_2...

I am not sure if there is in fact a classical description of how it occurs, but I’d like to know if there isn’t too!

Stress = F(restoring)/ Cross sectional area Stress = 2F/A

Hi, wrong forum but you guys might know so I try here. I have spookiness going around in my body with fluctuating fluid levels in the entire body, and the onsets are pretty random. Like someone vaccumed my fluids when I was sleeping. At one point I had clear elevated levels of testosterone...

I'm slightly confused by what medical professionals/scientists say when they say to limit exposure to x-rays/CT/PET, etc. scans if possible, due to radiation. I'm also confused as to why we're often told to leave the room when a relative is getting such a scan, given that medical staff that...

The human body is made up of mostly oxygen, hydrogen, nitrogen, carbon, calcium, and phosphorus. Less than 1% is sulfur, potassium, sodium, chlorine, and magnesium. If a human body was teleported to the surface of the sun, what would happen to these elements? Which ones would cease to exist...

Suppose a person is walking on the ground without slipping. For the free body diagram of just the person, only the frictional force is drawn in the horizontal direction. The force exerted by the leg muscles to generate a force against the ground is considered an internal force. What would be the...

Hoping someone can chip in and help me understand a problem when it comes to two-force members. I have a structure as shown below. Essentially its a single body attached at 3 points with pin joints. My question is, is it appropriate to treat each of the left and right side as individual...

So basically I need to find the coefficient of friction given the listed information. What bothers me is that I am getting two different accelerations for two different approaches. When I calculate acceleration using Fg=mgsin60 I do it this way: Fg=mgsin60 -> ma=mgsin60 ->a=gsin60 -> a=8.66. But...

The cylinder in question would have a moment of inertia of ~1.67kg*m² and rotational KE of 2.058J. At the point of impact also, assuming the body hits the sphere at a 90deg angle after traversing 90deg of displacement, it should(?) exert a force of 1.31N - enough to give an acceleration of...

Hi everyone! Do you have an idea which organs/parts of the body are ONLY functional on glucose? I would say the brain, pancreas, liver and kidney, but I have to take into account only those organs that are ONLY functional on glucose

I'm watching a video about " What is a black body?". That video said when the light interacts with the surface of a body, the electron and proton start oscillating. The electrons gain more transferred energy from the light that became its kinetic energy, rather than the proton because its mass...

I'm curious about impact on falling object, so i have taken initiative to solve this problem. I considered only force on the falling object would be its weight and taken F=mg. With only limited data m=.25kg and drop height h=1m. Pondering on this consideration practically, it will have more...

I would guess that by multiplying the pressure exerted by the shockwave on the body, and then the resulting force - here ~69 Newtons - per the distance the shockwave passed through when traversing body A, I could get the work done but I’m not sure if it’s that easy and whether or not I should...

Are we allowed to use free body diagrams in dynamic systems where there is non-negligible friction in say the rotational pivot between two linkages? If so, how to incorporate friction into the equations of motion? If not, what method allows friction to be accounted for?

Using these equations, I find L=0.02Nms, I=0.02Kgm^2 and KE=10mJ However, i don't think that this is the right method here.

Modeling the time evolution of the sun and earth orbiting each other using ##F = \frac{GMm}{r^2}## is straightforward. However, it appears that modeling the time evolution of the same 2 body system using general relativity seems to be a hard/intractable problem? There was in depth discussion by...

I was confused by how to work this problem in a rotating frame. The solution read that the centrifugal force on the mass should be of magnitude 𝑚𝑤𝑅^2. However, I thought it would be 𝑚𝑤𝐿^2 where L is the distance between the mass and the center of the circle (L = l + R). What am I missing here?

Is anyone very knowledgeable in making body or hand soap so can easily classify the main compounds' function and proportion Found on a body soap wrap written ingredient: Sodium Laureth Sulfate Laureth-4 Lauryl Alcohol Sodium Palmateiiii Sodium Palm Kernelate Palm Kernel Acid Paraffinum...

can you check if I sketched it correctly? And please if you know any good resources refrence it.

What is the connection between (1) Planck's quantum hypothesis that the oscillators of a blackbody can possess only discrete quantities of energy E=nhv n=1,2,3.. (2) the fact that the energy eigenvalues of the quantum harmonic oscillator wavefunction are also separated by intervals of hv...

So i got some equations but i think i am missing something, my main doubt is what is the relation between dx / dt and v(o) [ here] . Workings in attachment

If (a) is correct, the answer would be 34.3m. If (b) is correct, the answer would be 9.8m. I want to know exactly which one is meant by the question and the reason behind that. Personally i think its a.

I recently read that there is enough hydrogen in the human body to lift 195 lbs off the ground. I know this sounds super-silly but if we ever develop nanites; could they manipulate the hydrogen and allow us to float?

https://en.wikipedia.org/wiki/Wien's_displacement_law "Maxima differ according to parameterization ... Using the value 4 to solve the implicit equation yields the peak in the spectral radiance density function expressed in the parameter radiance per proportional bandwidth. (That is, the density...

Hello, I am currently working on the proof of Minkowski's convex body theorem. The statement of the corollary here is the following: Now in the proof the following is done: My questions are as follows: First, why does the equality ##vol(S/2) = 2^{-m} vol(S)## hold here and second what...

This is my answer: $$KE_{total}=KE_{centermass}+KE_{uppermass}+KE_{bottommass}$$ $$KE_{total} = \frac 1 2 (mv^2 + 2m(\vec {v} + \vec {wL})^2) $$ But, the solution manual says that the answer is this: $$KE_{total} = \frac 1 2 (mv^2 + 2m(v^2+w^2L^2)) $$ I think he regard this composite body as...

I'm interested in chemistry but it's all new for me and I'm just starting out. I tried to do some calculations but got stuck... I was wondering, for example a supplement has the following values: Molar mass: 306.247 g mol-1 Tmax 2-4 hours Cmax 363.3 ng / ml Half life: 11.21 hours How do...

Here is the hint that the book gave me: "For the maximum value of μ, the rod must be to the extreme right i.e. horizontally rightwards of the axis of the pipe" I think what it meant is the same as this: Note: in the calculation below, ##r## is the distance from the center of pipe to the CoM...

Hello everyone! So I've been studying gyroscopes, and see that a torque about the shaft alters the momentum, we can find the new momentum vector by finding the torque, multiplying by a small amount of time, and finally adding that vector to the momentum vector. This will create a precession for...

Hi, A body with center of mass behaves as a point mass when a force is applied. So when ##F_{ext}=0## then does it also behave as a point mass with ##a_{com}=0##, at rest. If yes, How can we prove this? (And can somebody please answer my other question I posted a week ago...

I'm sure this is a strange question, but I am really curious as to whether the human body can produce electromagnetic pulses. And particularly, whether an orgasm is a type of EMP. Wikipedia says an orgasm is "a sudden discharge of accumulated sexual excitement". So is this discharge of...

Three (many) body problems where three or many bodies (particles) interact are impossible to solve analytically. First one appeared in classical mechanics where equations of motion of planets were tried to be found by applying Newton's 2nd law for system of planets and stars interacting via...

While studying two interacting particles such as a Hydrogen atom, I learned how to reduce the problem into two independent parts by using center of mass coordinates and the relative coordinates. The resulting two independent energy eigenvalue equations give me two eigenvalues for energy as...

Hello all, I have some issues understanding the inertial-frame (or global-frame, G-frame) versus the body-frame (B-frame) when it comes to simulating the motion of a rigid body in 2 dimensions (planar body mechanics) in a system of ODEs. I have been self-learning from textbooks on simulating...

The image above is the solution posted by the book. I can follow the reasoning that has been used, but i have a trouble particularly at the first equation itself. Why should $$n = 2 \rho / m_{H} $$ instead of $$n = \rho / (2m_{H})$$, since the mass os a molecule of hydrogen is two times the...

if a body is pivoted at a point it is quite easy to calculate the torque as we know the axis of rotation. but, if a body is under free fall and we apply a force of F Newtons at a distance of x from its centre of mass , then how do we determine the axis of rotation?

hello according to GR gravitational force is not a real force rather a space time curvature ok a body in motion follows a sort of invisible rails why doesn't a body at rest remain at rest, then ?

Summary:: Looking for a certain degree program What kind of degree would be best if I really wanted to get into studying energy within and around the human body and interactions of it between electronic signals and things like that? I am really starting to believe that our understanding of...

##W=mgh=100(\sin 37)2=-120J## Right answer! But the question is asking work done by the person. So again I wrote two eqns ##F_N\sin 53+F_D\sin 37-100=10.2a_y## ##F_N\cos 53-F_D\cos 37=-10.2a_x## I just need ##a_x## and ##a_y## to solve.

Can you pull down/hold more weight than your body using your muscles? Imagine a 1 to 1. One side is suspended 190 pounds, the other is me, 175 pounds. Can i, using my muscles and standing on the ground, hold that suspended weight off the ground? I understand if i lock out my arms and...

I guess that the reason that objects fall over is that there is nothing to hold it's center of mass. So what I want to do is to work out how fast in Delta intervals it would rotate and fall over.

I know it isn't possible for any mass/massless body to have velocity more than the speed of light in vacuum but what if it was done hypothetically? As far as I know length and time of an object undergo a transformation so that the laws of physics remain same between observers at rest and...

Back in grade 10..,.( Oh my that was awhile back 😀 ) our electronics teacher passed around a multimeter and everyone measured their resistance ( a lead held in each hand, Fluke was set on infinite ). All in the class measured between 700K and 800K approx. All except me that is. I measured 1.4M...

Hi, I have an issue with understanding the body forces in the context of FEM simulations. I am using freefem to do the simulations. So I took a simple unit cube, fixed the displacements at side ##x=0## and prescribed a displacement ##u_x = 0.025## at ##x=1##. If required, the entire script is...

In this diagram, if the system begins by being held static, and then at time ##T## release of all components occurs, at all times ##>T##, until vertical movement stops upon vertical block ##m## making contact with the Normal Force at the base of block ##M##, will the lateral acceleration of...

It's a pre-print from a bunch of researchers at the NIH. https://assets.researchsquare.com/files/rs-1139035/v1_covered.pdf?c=1640020576 No wonder Long Covid exists! ?:)

does anyone have a good reference on the history of calculating the standard gravity parameters of solar system bodies? My guess is a rough estimate of Jupiter's SGP can be gained from observing the motion of its moons, in which case the first estimates could have been made soon after Newtonian...

Hi, I have some soft body equations that require first order elasticity constants. Just trying to figure out the proper indexing. From Finite Elements of Nonlinear Continua by J.T. Oden, the elastic constants I am trying to obtain are the first order, circled below: My particular constitutive...