Body Definition and 1000 Threads

I would like to patch some gaps in my physics background. For example, I've been trying to come up with the sollution to the following: I have a model rigid body made up of two mass points and a massless rod connecting them. I throw the body with initial velocity under some angle of elevation...

Hi, I am trying to find out Force on a rigid body when it is completely inside a fluid with density p, i.e. the body is completely drowned in the liquid and then another liquid is pushed into the container with different density 'r' (such than r > p). Thanks.

Looks like a good step forward. (At least to someone far outside the field. :biggrin:) Abstract and paywall article in Nature. https://www.nature.com/articles/s41586-019-1833-8 Full preprint at: https://arxiv.org/abs/1909.05272

I use the moment of inertia I = 1/12ml2 for an axis perpendicular and passing through the center of mass of a rod. In a cube built out of 12 rods I have 8 rods at a perpendicular distance l/2 from the axis through the midpoint of a cube. These 8 rods contribute the moment of inertia I1 =...

First of all, this isn't homework, so I'm not sure if this is the appropriate channel to post this in. I study physics as a pastime and I simply want to know how to solve this problem. I'm willing to do all of the work, or none of it, as long as I understand the solution! :smile: Because the...

I was looking at Kirchoffs Laws: "A solid, liquid or dense gas produces a continuous spectrum". I would expect objects to produce an emission spectrum since we would be observing the photons that come from spontaneous emission of electrons in excited states. This photons are specific to the...

To start off with, I can't seem to interpret the FBD here. Here are my drawing: and what I interpret as. From here, I feel like I can (it's wrong obviously but I'm not sure why) state that sin theta = o/h = o/mg = N/mg , so N= mg sin theta? Thanks

Regarding calcium in the bloodstream, in drinking water, and in food. Are calcium ions always single, free atoms? Is that the definition of "dissolved?" (single atoms?) Does the bloodstream contain any undissovled calcium? how much? how big? Does drinking water contain any...

I do not know where I am doing wrong. I asked a tutor, he said I was doing it correctly. Below is my work. Please help! Net loss by radiation in 10.0 mins is 74.8 kJ

Greetings, I'd like to simulate a complex mechanical automaton with lots of gears, cams, levers and springs. Most of the parts are going to be 3D printed except for some metal springs, rods and bearings. I want to make sure everything fits together and works as expected. Here is just a small...

After emitting two photons (or any other kind of energy) in the direction of motion and in the opposite direction, the velocity of the body (a big charged and unstable particle) remains unchanged, while the kinetic energy decreases. This entails a decrement of the rest mass, or of the inertia of...

I would like to know, how it ends? You can give me spoilers. As far as i know, he goes even to end of the universe, and right now, i am not interested in a total depressing ending. It looks like, that in his vision, the universe is such a hostile place, that it would make Lovecraft proud.

Hi everyone! I have started to study physics this month and I got to the Newton's laws. According to Wikipedia, the first law is: This definition made me wonder: If there was, let's say, a fictional road, infinite long and frictionless, and a body would move in constant velocity over it, could...

Sorry if this is a stupid question but I couldn't find an answer anywhere. According to 2 scientific papers, the neutron star PSR J1748-2446ad has a rotation rate of 716Hz, which equates to a linear surface speed of 0.24c. What if this star was originally rotating, let's say, 5 times (or more)...

Has anyone created a thread on Free Body Diagram on assembly having many components ? For example a Casing having premium threads in both end and a set packer within it. What would be the FBD equations to determine various forces and reaction forces

I created a 2 body simulation Is there some special conditions where I can test their trajectory and check my code ?

The thing is that my professor said that if the velocity of ##A## is ##400 cm/s##, the velocity of ##B## is ##200 cm/s## because "##B## is connected to two parts of the rope and ##A## is conected just to one part", and he also said that that ##200 cm/s## is the velocity of ##B## with respect to...

I am trying to create a simulation for a gravitational 2 body problem. But I am kind of having trouble to define the equations that can be solve numerically. From an inertial frame I defined the position of the two objects as the ##\vec{r_1}## and ##\vec{r_2}## with masses ##m_1## and ##m_2##...

Here, I have two doubts 1) if the surfaces are frictionless, then there's no force being applied on the ##x' axis## of ##m_1## except from the weight, so it should be sliding, shouldn't it? So, there's no force that I could apply to ##m_2## to keep ##m_1## in equilibrium since any force that I...

Why is the gravitational potential energy of the chain's center of mass equal to the total kinetic energy of the disc after it was fully wrapped? My first thought was to write ##E_{0}=(M/2+M)g∗2πR=E_{f}= Ep## (from the chain) ##+Ec## (from the disc). Instead he wrote ## mg \frac{l}{2} ## = ##...

FIRST PICTURE I have some doubts here because of the spring... I'll tell you what forces I've drawn. For ##A##, I drew the weight and the force applied by ##B## (the normal force) on the vertical axis; and the elastic force pointing to the right on the horizontal axis. For ##B##, I drew the...

Summary: Will the motion around us become faster when we travel faster? When we approach a body rotating on its axis with certain speed v, will we see the body rotating in speed slightly more than the v during our motion ?And what happens assuming that we are approaching the same body in speed...

Homework Statement: Object inside liquid Homework Equations: T=k*v^2 F=m*a We hold an object with a mass (m) inside a liquid. On t=0 we free the object. Except the weight there is another one force, the friction of the liquid, witch is T=k*v^2 ( v=instant speed, and k=constant > 0). Also...

Stokes' Law gives us the value fo viscous force when a spherical body is under motion inside a fluid. ##F_{viscous} = 6\pi\eta av## (where ##a## is the radius of the spherical body and ##v## is the velocity with which it is moving) What is the reason for the Viscous drag to depend upon the...

Where I find the wiring diagram for the throttle body in the link? https://www.eurofrance.pl/en_GB/p/Air-Throttle-Body-192300-2010-0R011-Toyota/65407?currency=PLN

I am not able to understand why normal force on top in a vertical circular motion the least. Also please help me with normal force of a body over convex and concave bridges. Why do we get these equations: N=mg-mv2/r (convex bridge) N=mg+mv2/r (concave bridge)

Why a massive body is easier to break than a tiny body despite the force bonding two particle is the same?

I am reading Landau's Vol 5 on Statistical Physics and have trouble grasping some concepts in Section 20. If I understand this correctly, the body and the medium are in direct contact and can exchange work and heat while the object can only exchange work with the body. So the minimum...

Why when we supply energy for biological body then the body can keep entropy not increase?Because we know that by definition temperature equals partial derivative of internal energy to entropy.So that when temperature being constant,if internal energy increase(supplying energy for body) then...

The question doesn't specify whether we're talking about translation or rotational equilibrium, so I suppose it's both: In order for the body to have translational equilibrium: 60 N + F2 = 0 F2 = -60N However, in order to have rotational equilibrium: 60 N * 3m + F2 *8 m = 0 60 N * 3m - 60 N...

Usually when setting up an energy equation I use the general form, (Initial KE) + (Initial PE) + (Any other work done to the body) = (Final KE) + (Final PE) ... For this I said the initial GPE and KE are 0, and the work done by the field is GMm/x (derived by integrating a force of -GMm/r^2 from...

Summary: In the situation given, all the surfaces are friction less, pulley is ideal and string is light, F=mg/2, Find the acceleration of block 2 ? Here's the diagram-- My attempt- (i) I tried to solve the question by making FBD of the two blocks, but i am not able to draw all the forces...

For bound system to form it must radiate away binding energy. By mass energy equivalence mass of the bound system is reduced proportionally to amount of binding energy. The question is from which mass this "binding mass" is subtracted. Common answer that I have seen is that this binding mass is...

When only force acting on body is a central force, angular momentum is constant and given by: L = mr^2 * w where r is distance from origin, and w is angular velocity. Angular momentum can also be written as following: L = r x mv = rmv * sin(theta) where v is tangential velocity, which is...

Good morning all, How do you calculate the air pressure exerted on an average human of 1.9m2 I know the air pressure is 1.01kPa. Do I do, F = PA? 1.01kPa x 1.9? What are the calculations step by step? and what is it in bars? Does that mean it is 1.919 bar? Thank you,

Hi I would like to know the facts about this

I modeled a throttle body in Simulink. How do I model the position of the gas pedal so that if the position of the gas pedal changes the input voltage to the throttle body actuator will change and open the throttle? why should i give on the left side to get position of the gas pedal from the...

Problem in the picture. I have a question regarding the problem in the picture. Ma=0 -2Kn*1a+By*4a=0 --> By=0,5kN Mb=0 2kN*3a-Ay*4a=0 --> Ay = 1,5kN Ax=0kN Ay is the pin support and By is the roller support. According to the solution By should be 1kN but isn't that the wrong answer? 2kN has...

Hello Ihave gotten as far as coming up with an equation for the sum of moments and it goes as follows: bh*1/2b-1/2hb*1/3b=0 the answer for h i get is wrong and i don't know if i am missing something. moment arm on the b is 1/2b and the moment arm on h is 1/3h because of the way water pressure...

Hello, Wanted to know if this was the correct approach to solve this example. I uploaded the question along with an attempt. Thanks in advance.

So looking at the solution, FBD for A makes sense: Normal points inwards, gravity and friction oppose each other, with friction pointing up. B confuses me: the solution says there is only Normal and gravity pointing downwards, but if "the sphere rolls without slipping during the entire motion"...

Hi,everyone. Recently, I am studying green's function in many body physics and suffer from trouble.Following are my problems. (1) What is the origin of the definition of green's function in many body physics? (2) What is the physical meaning of self energy ? It seems like it is the correction...

if we have known the density functionρ(r),and then we can calculate the total mass of a spherical body. M=integral of ρ. Now we will say that body has mass M, but I think it is wrong. according to special relativity, mass is equal to energy, so we can also say that body has total energy M,but i...

The rate at which glucose enters the bloodstream is ##r## units per minute so: ## \frac{dI}{dt} = r ## The rate at which it leaves the body is: ##\frac {dE}{dt} = -k Q(t) ## Then the rate at which the glucose in the body changes is: A) ## Q'(t) = \frac{dI}{dt} + \frac {dE}{dt} = r - k...

Hello, I'm trying to simulate the trajectory of the decay of two protons from the nucleus. I am using classical physics to calculate the trajectory from Newton's second law. For this, I wrote a python program, but I'm not getting the expected result, which would be an exponential path. My...

Hiya, I was wondering if one of you clever people here could just affirm something for me. The three body problem : https://en.m.wikipedia.org/wiki/Three-body_problem In classical mechanics. Some background, I wanted to write something in a blog about theory and reality and the differences...

So my basic understanding of an integral is that it finds the area underneath a graph. I understand the idea behind an integral being the summation of f(x) * delta x, where delta x approaches zero. If I look at the integral it's telling me that there's a change in mass that is being...

I am quite confused, as I start this question. I can easily find the following when searching up Planck's law: However, this is not u. My prof is quite unclear and sometimes chooses his own variables as he sees fit, so i am not sure if this would be equivalent to what he is looking for u(λ)dλ...