Body Definition and 1000 Threads

Okay guys, a different one for you. I am in the planning stages of building a structure that will simulate a motor vehicle collision. The process would be a motor vehicle will be hoisted to a specific height and then dropped. The height, and the weight of the vehicle will determine the...

Archimedes principle of the force of upthrust = weight of water displaced by the body immersed , but is this law independent of the shape of this body. If we use the idea that the upthrust = P*A on the lower side - P*A on the upper side , if we use it on a rectangle or a square , the only change...

I am currently working through Griffiths' textbook on quantum mechanics. The hydrogen atom was first modeled as a one body system with the proton fixed at the origin. In this case the potential was given by Coulomb's law, V(r) = -\frac{e^2}{4\pi\epsilon_0}\frac{1}{r} \ , where r is the radial...

It should for nitpicky convenience's sake, be pointed out that unless the point we choose to calculate the moments around is the C.M of the rigid body, or that the the point moves parallell (including being at rest) to the motion of the C.M, we get an additional term on the RHS.

When a Rigid body is said to be in planar motion, if all all the particles in the Rigid body moves in same plane and these planes are parallel to each other. I think i misunderstood this definition especially the particles moves in same plane and these planes are parallel to each other...

Why can't the atoms along the edge of a body centred and a face centred structures touch each other? Is it something to with the reasoning that somehow if they were made to touch each other then we would not be able to get the face centred and body centred structure?

Hello! I am hoping someone could help. I have no idea where to start on this, and have been flipping pages for an hour or so trying to figure it out. Find the spectral range Δλ over which a blackbody's intensity B(1/2) is brighter than half of its peak value B(peak). (In other words, find the...

Here is the question: I have posted a link there to this topic so the OP can see my work.

Hi, I've got a simple question regarding the maximum of the spectral energy density in Planck's black body radiation. It turns out that if you calculate which frequency has the most power associated with it (i.e. maximize R(\nu)), then you do it with wavelength as well, and compare, they're not...

http://en.wikipedia.org/wiki/Dashi-Dorzho_Itigilov Is there any explanation for this? Maybe he pumped himself full of some kind of chemicals before he died and told them to exhume him, considering he knew medicine and pharmacology?

I have a question regarding forces in meniscus. Lets assume we have capillary 1cm in diameter. We pour some water into the capillary. We will observe concave meniscus. If we add some water (so water level exceed the height of the capillary) we will observe convex meniscus. Not let's...

Suppose a block of mass 5 kg is resting on a horizontal surface and coefficient of static friction between block and surface is 0.2. If the block is pushed against a vertical wall with a force of 200 N, will the static friction oppose the force? The body has no intention of moving as it is...

Could there be complex life somewhere in the universe with body temperatures averaging 80 degrees F? I am curious if life of some kind could survive a body temperature that low and function normally.

This is not a joke. Is it by all accounts impossible to do this, supposing that an artificial heart with artificial blood transport systems (that provide oxygen and all needed nutrients) were used to keep the cells from dying. Also, assuming the brain was yours, what would it feel like to...

How does the amount of heat absorbed by a body depend on the mass of the body and surrounding conditions such as pressure?

I don't really understand how to calculate the stress in a deformable body that is unconstrained and acted on by an external force. For example, consider a rod with a circular cross-section lying parallel to the x-axis. If one end is constrained from translating in the x direction and the other...

Homework Statement A car and a trailer are connected by a joint. The car and trailer system are on a inclined place at a gradient of 8 degrees. The rolling friction coefficient along with other vehicle parameters are given.We are asked to draw the free body diagrams of the car and trailer...

Good evening, I've been trying to wrap my head around this problem for some time and I just can't seem to get it straight. What I am trying to achieve: I want to program a recursive model that calculates the position of a moving body in a fluid after a certain time. What i have done...

Hi, This is my first post here, so if I make mistakes please be gentle with me. I have a 'problem' with a solar system I'm developing for a series of stories I'm writing. Those stories have nothing to do with Earth, and are set in a system unlike our own. To introduce the system, the...

why or how does an object emit radiation of different wavelength for a given temperature?

Hi, I am using a Human body model which I built for some simulation studies. I was trying to pass DC current through the Human body and though my Project completed the simulation successfully I got the below warning message. Can anyone please help me interpret it? The error log is as...

Hello all, Is there any really good software, package or otherwise, that is helpful for simplifying long operator expressions, particularly with (anti-commuting) electron operators? For example, I'd like to be able to transform Hamiltonians, project onto subspaces with specific occupation...

Homework Statement From Young and Freedman's University Physics, 9th Ed., Problem 4-49. Two blocks are connected by a heavy uniform rope with a mass of ##4.00## kg. An upward force of ##200## N is applied to the top block, which has a mass of ##6.00## kg. The lower block has a mass of ##5.00##...

Homework Statement W(oa) = -5k α(oa) = 3k B = 30 deg B(dot) = -2cos 30i + 2sin30j = Vrel b(double dot) = 4cos30i - 4sin30j) Homework Equations Va = Woa x Rao + Vrel The Attempt at a Solution This is such a simple problem and I don't know why I am messing it up. I am just...

Ok, so I am tryting to calcualte the mass of an orbiting body. I am using M = 4 * PI^2 * r^3 / ( G * T^2 ) Lets use the Earth as an example. However I am not getting what Nasa has for answers of 5.9 E24 kg. http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html Using this...

Alright, let's get down to business. How important is it for you to be the best and sexiest scientist. We may be spending a lot of time in the lab but how much time are we spending sculpting our bodies at the gym :wink: and the mirror every morning! Also, feel free to comment and...

Hi. Consider a solid body placed in vacuum. How much is its pressure? Can we describe this body using thermodynamics if its pressure is zero?

Blue-ring octopus' have this. It binds to Na channels in nerve cells. I don't know if you guys know this in here about biochemistry, but it includes a marvelous story of mimicry. Anyways, I was just wondering if tetrodotoxin looks like something, in the same way that LSD looks like...

Hello, Am not studying biology am engineer but iam just wondering if it is possible to make a muscle contract through external voltage maybe through some electrodes connected to some area on the skin. Regards Hisham

My boyfriend is into magic, and he has a device that sends a small current through his body. His shoe has an electrode that is activated by a magnet in his other shoe; a wire runs up to a battery. As long as he is standing and grounded, it allows him to channel a small amount of electricity...

Why is finding the gravitational force on the center of mass of a composite body the same as finding the gravitational force on each individual constituent of the composite body?

Is there any possibility of transfering the total charge of a body, in another body, by the process of "conduction of charge" ?

Why is the angular velocity and angular acceleration(if the rigid body has some) same for all points on a rigid body?

Do you normally write the magnitude of the vectors in free body diagrams? I have homework on this. Is there any convention when writing the magnitude?

Hello all, I always read in texts that you can charge a body in air till the the electric field due to body does not exceeds the dielectric strength of air, which has a certain value. The question that is popping into my head is that, what if we charge the body in vacuum? I expect...

I was wondering about the spectral radiancy curve of a black body. How does the spectral radiancy of any other body looks like. I have seen one among many possibilities: http://www.giss.nasa.gov/research/briefs/schmidt_05/ Q 1. But i was thinking that for a general body (not a black body)...

Homework Statement As shown, a uniform beam of length l = 5.90 and 48.2 lb is attached to a wall with a pin at point B. A cable attached at point A supports the beam. The beam supports a distributed weight = 21.0 lb/ft. If the support cable can sustain a maximum tension of 300 lb , what is...

I apologize upfront, as I have no experience with math to begin with. However, I have a real life problem I am trying to figure out here at work and I would appreciate some help. Here is my situation: Homework Statement In a 3 dimensional plane, I have an artillery piece pointing at...

Let's consider a stationary ball lying on the floor. The weight of the ball acts downwards and the normal reaction acts upwards. They are of the same magnitude but not of the same type. So normal reaction is the reaction to what, if not weight ?

Given some body with a constant force F acting on it upwards (The body is subject to the gravitational force due to the earth) What's the correct statement? Or: K - Kinetic Energy

Hello All, Is is possible to the derive pitch, roll and translational acceleration, and the location of pitch and roll axes from a set of tri-axial accelerometers mounted on a rigid body? My initial though is that 3 accelerometers might be sufficient, but not sure. I need to do figure out the...

Recently on an aquarium related forum, I called out someone for making what I considered to be an outlandish claim and I was supported by several others. However I wish to get the opinion and/or facts explained by someone from a purely scientific standpoint. This has to do with the heat...

Homework Statement A man is on an elevator - Draw a FBD of the man if the elevator accelerates upwards - Draw an FBD of the man if ele. accelerates downwards Homework Equations F=m*a w=mg The Attempt at a Solution My FBD For the first one "elevator accelelartes upwards" means...

Hello. My first post here. I'm having trouble with the basics of rigid body rotation. I have a few questions (my apologies if they are too childish; I'm very new to this): 1) Is torque (and other angular parameters like angular velocity, angular acceleration etc.) defined about a point or an...

I'm modeling a single 3D rigid body in preparation for some more complicated modeling in order to gain a better understanding of Euler angles, the angular velocity vector and the rotating coordinate system. The body is rotated in inertial frame by an intrinsic ZXZ rotation, with respective...

Say, a body of mass 'm' is thrown at a certain angle with the vertical with certain initial velocity 'u'. The initial momentum of this object is mu. Am I right to say that if it spent 't' seconds in flight and came back, its final velocity will still be 'u'? And the change in momentum will be...

Let us consider the case of a body falling down radially towards a Schwarzschild black hole. The velocity of the body is as high as it would be if it had been falling from standstill at infinity. When the body finally fuses with the black hole (get infinitely close to the Schwarzshild...

Hi all, new user here and straight in with a question to help me understand something. Not sure if I'm in the right sub-forum but oh well. Regarding circular motion and centripetal acceleration, we're given the classic example of a cyclist leaning into a corner to create a general equilibrium...

Direction of force acting on a body in uniform circular motion?? Hello Sir/Ma'am I'm a a novice. I joined this forum to clear my doubts and improve my physics. Here is my question.. " We generally say, frictional force always acts in a direction, opposite to the direction of motion of a body...

E.g. you cut yourself in the finger. The cells seems to know they will become part of your finger. (No lung tissue will be formed in your finger)