Body Definition and 1000 Threads

Does anyone know why the resonant frequency of a grounded human is smaller when ungrounded?

Homework Statement A cavewoman is dragging her 65.4 kg mate home, up a gentle 10° incline. The co efficient of friction for skin on oil is 0.40. What is the minimum applied force she needs to keep the neanderthal moving with uniform motion? Homework Equations ff=μFn fg=mg fnet=ma The...

Is the Pineal Gland behind the Body Of fornix? I look at so many photos and it look like it is right behind the Thalamus but inside the body of Fornix?

2 Questions about statics of rigid bodies Homework Statement A cable of length 8.5 m is attached to the two posts as shown in Fig. 6. The crate has a mass of 1000 kg. Find the x and y components of the forces exerted by the cable on the eyebolts and find the tension force in the cable. The...

In the framework of Classical Mechanics,there is no problem in the rotation of rigid body.But I want to make the concept about rotation more clear. About rigid body ,there is no vibration;it would only rotate and translate.We can easily distinguish translation from rotation in rigid...

Hi, I'm trying to understand black body radiation but I have two conflicting descriptions (both reputable sources). Maybe both are true, but I need some clarification please: 1. A black body is a perfect emitter – it will emit equally well at any wavelength. 2. The black body re-radiates...

If, in a problem, I want to know if a given force is body force or not, what should I do? for example- a rod rotating about an axis, how will I know if the centripetal force is Body Force or not? (body forces are those forces which depend on volume)

What is the main difference between Solid body and Rigid body ? Can you give me example some of them !

In the above figure, what would be the time period of the body(in red) under gravity, neglecting any non-conservative forces? And what do call this type of situation? A gravity well or sth?

hi All, We know from QM that black bodies at temperature T emits light in a well stabilished patern. Now what if the body has color? Which is the emission patern of a green snooker ball for example, at temperature T? When scattering white light we see this ball green because it absorbs...

I have a beaker with a liquid of density rho, and weight = W now I throw into it s Bob say, of density rho' and weight=w. can anyone explain what will be total new weight,with all forces explained for the cases: body floats. body sinks

Homework Statement Problem figure The rigid body assemblage shown in the figure above, has a force P(t) acting upon it (varying with time). Pick a generalized coordinate such that a single degree of freedom equation of motion can be written. There is a black, massless, rigid bar. Call this...

I want to output an excel file with the results of the trajectories of a two body problem, with initial position and velocity. But my program is not compiling. Any suggestions/problems that you can see? #include <iostream> #include <vector> #include <fstream> using namespace std...

Hi guys new to the forum - sorry if I'm not as advanced as you lot :-p I'm currently only at A Level in my adventures of Physics! (I didn't think this would fall under homework help, I apologize if it does) Anyway, tomorrow in school there is a house technology project, and I've been entered...

Hello, I just have a conceptual question about my project. I am designing a two stage MOS opamp. Upon determining my Vin common mode low, I realize that while calculating the voltage threshold including the body effect that value is only valid at VCM, min. As the input changes so does the...

Hi, how to calculate the force on a charged conductive body (ball), when that body is between two parallel plates (+V, -V) (see image), ooh and I am calculating numerically. I would first calculate the surface charges on the conductive surfaces (2 disks + ball), then calculate the potential...

Homework Statement Homework Equations The Attempt at a Solution I found out the distance between the star and companion which I calculated as 1.11x1010m (Ignoring the mass of the companion).Then I calculated the radius of the stars orbit, using r = vt/2∏ since vt =...

Homework Statement I just saw the equation R=R'Ω (where ' is dot, or the derivative) in my notes (unorganized obviously), and can't remember what it stands for (rotation matrices?). Can somebody please tell me what this equations means thanks. I know R is some position vector and Ω is the...

I have to run a FEA analysis on a nozzle check valve body DN700... Its been to a professional engineer and he has completed the study so I am trying to do it myself to get to know the software better... I'm using PTC CREO 2 mechanica as the software... Attached find a picture of the valve...

Hi everyone, I have read a few different ways of looking at this problem, and it's one of those things where I am happywith the answer, just not how to get there using proper mathematics. My lecturer described this with some complex integrals involving E (but I'm not sure what that is!) but I...

I'm not sure which group this question really belongs to, so "general physics" sounds like a safe bet. This question was prompted by having listened to Neil deGrasse Tyson's more philosophical views about our nature and our connection to the universe, which are quite insightful. Most of...

Homework Statement A 180 lb man weighs 5 lb in water. What is his percent body fat? Assume that fat has a density of 0.90 g/cc and muscle has a density of 1.06 g/cc. Water has a density of 1.0 g/cc. Although we are given the weight in lbs, it is okay to work with it like mass (as grams) or...

hey everybody :) i am new here and i need ur help. I have to solve this problem for home work tomorrow.Topic is forces in the body. I attached it. I actually need help for the whole first question. thx u in advance. Please try to explain it not too difficulty. thanks u :) Homework...

Homework Statement A disk or radius b rotates about a rod in its center with a constant angular velocity, Ω. At the disk's edge A, a pin is attached allowing for a body to be attached an freely swing during the rotation. Determine the differential equation for the angle β between the attached...

Homework Statement A perpendicular force F acts on the tip of a thin rod of length L and mass M in the ij-plane which is not fixed. What is the translational and rotational acceleration of the rod about the center of the rod? Homework Equations At first it seems like an easy problem...

Homework Statement I'm having some trouble understanding "conceptually" the following problem (example 6.18 in Kleppner and Kolenkow.) A stick, initially upright, starts falling: find the speed of the center of mass as a function of position. Homework Equations Work-KE thm. for a rigid...

Homework Statement Suppose the ruler in procedure 3 is asymmetrical, balancing at the 60.2 cm mark. The ruler is now supported at the 41.3 cm mark, and a mass of 364 g is placed at the 26.2 cm mark. Find the mass of the ruler. The ruler is 1.00 m long. Homework Equations...

Homework Statement If you lie on the ground at night with no cover, you get cold rather quickly. Much of this is due to energy loss by radiation. At night in a dry climate, the temperature of the sky can drop to -40°C. If you are lying on the ground with thin clothing that provides little...

A general example of a linked body is an object that is made up of rigid bodies joined together by pivots, such as hinges and ball-socket joints. If the pivots are frictionless, and I apply a force to one rigid body, how can I go about describing the subsequent angular acceleration of the...

Homework Statement Two bodies travel the same distance. One body travels half of the distance with the speed V and the other half with the speed 2V. The second body travels half of the time with the speed V and the other half of the time with the speed 2V. Which of the bodies has the higher...

Hi guys, I can't get my head around the centre of mass of a submerged body at all. the notes I've been given don't actually state how you calculate the centre of mass of the submerged body at all and just state it with no decernable pattern. I did assume that it was the centre of mass of that...

Homework Statement In the image below, calculate the center of mass (x-bar,y-bar) of the composite body. Homework Equations I've used all of the equations for area for the shapes needed (triangle, square, circle). The Attempt at a Solution I have attached my calculations and...

Strange title? Basically, a few days ago we got a dead rat in our ceiling, which is covered in insulation. Took a while to find it, but it got me thinking, how would you detect a dead rat body? If it recently died, I first thought you could use thermal imaging (aside from the expensive aspect)...

Homework Statement A 0.9 kg mass at (x, y) = (20 cm,20 cm) and a 2.0 kg mass at (20 cm,100 cm) are connected by a massless, rigid rod. They rotate about the center of mass. Homework Equations x=(m1*x1+m2*x2)/(m1+m2) y=(m1*y1+m2*y2)/(m1+m2) I=1/12*ML^(2) The Attempt at a...

i was reading about derivation of Euler's equations for rotational dynamics (john taylor, classical mechanics, chapter 10) when i got stuck on one of the reasonings essentially it refers to the moment of inertia tensor, since the tensor itself about a point is dependent on the position of the...

Homework Statement A small body is set on the surface of a smooth sphere at an angle of 45 degrees from the center. At this point the sphere is given a constant acceleration in the horizontal direction of 9.8 m/s/s. There is more in the question, but the goal is to find when the body will...

This is more of a math question I suppose, but its in the context of calculating the second order energy shift in the ground state energy for a non relativistic collection of electrons. We end up showing that the energy shift has a finite and divergent piece. The divergent bit is proportional...

So I am writing a program in python to do RK4 for the two body problem. I want it to display a sphere moving around another. It currently displays one sphere for a split second and then it goes blank. Any suggestions? from __future__ import division from visual import * from visual.graph import...

So I derived this equation for the net force/acceleration of a motorcycle on a flat surface. I believe this equation could practically be used for any rolling object. ƩF = Fp - μ*Fn - FD Where: FP is the force of the bike acting against the ground, tangent to the ground FD =...

Is there a way to predict the motion of a non-rigid body?

First off,I would like to apologise for not introducing myself. I have yet to find that certain part of the forum,but if the mistake was on my part,mods please direct me. Now to go to the real issue. This is something I've long "gotten over",meaning it was in the introductory lessons in...

Homework Statement Four point masses form a rigid body (they are connected by massless rigid rods) given the positions M1= 3kg (2m, 4m, 0m) M2= 2kg (1m, -4m, 0m) M3= 1kg (10m, 2m, 0m) M4= 5kg (-5m, 2m, 0m) Find: A) Moment of inertia of this system when it rotates about x axis B) Moment of...

Hi, When looking at a photo or sketch, I find it hard to take out the important bits and turn it into a freebody diagram. I am doing this question (pic attached). Im quite unsure how to even begin. I've though of a few ways to start analysing it. The first way analyses AD as a whole. And...

where is the biological clock in our body? how does it effect us?

Homework Statement Equate the expression for centripetal acceleration with the gravitational acceleration to show that the central parts of the galactic rotation curve are consistent with rigid body rotation. The attempt at a solution Say a star near the galactic center has mass m and the...

Homework Statement It's not exactly a homework question, just want to see if i have the right concept in drawing free body diagrams See attached Picture. In case 1, the object is fastened on plane x-z and the rectangular block is fastened to the T-block in y-z plane. Will the force be...

Homework Statement Hot oil, Hot water, Cold Oil, Cold water Homework Equations Upthrust according to flotation principle The Attempt at a Solution It will weight lightest when Upthrust by the fluid is highest, which should be cold water. Answer given was " cold oil".

I'm just learning how to use Ansys Workbench 13 to analyze static structures. I need to analyze the deformation of a simply supported beam with a concentrated force in the center vertically downward. I have a 3D model of this beam created in Solidworks. How do I create a force in the center...

Hello, Does anyone knows why rigid body does not exist.So in order to know its history which textbook can i refer to ? For example to know classical mechanics properly you have to go to Newtons book known as Principia. In order to know rigid bodies who should we refer.

Homework Statement If a body is charged by rubbing it, its weight a) may slightly increase of slightly decrease b) increases slightly c) decreases slightly d) remains constant Homework Equations The Attempt at a Solution I know weight is nothing but gravitational force...