Body Definition and 1000 Threads

Homework Statement At a construction site, a small crane is raising two boxes of nails on a plank to the roof. One box has already been opened and is half full, while the other box is new. The boxes, including the nails, weigh 10kg and 20kg, respectively, and are both the same size. If the...

Let w = (w1, w2, w3) wrt to the body frame of a rigid body, where the body frame is right-handed orthonormal. I have gathered 2 definitions of w from different sources and I am confused at how they connect to one another. One is that the RB rotates about w through its CoM at rate abs(w), the...

Homework Statement Bicycle with a rider applying weight to on pedal. Draw as free bodies in equilibrium. There are different situations. Homework Equations N/A The Attempt at a Solution So I am working on part a). 1. I believe it is only referring to just the pedal, chain, and the two...

Homework Statement Two equal bodies with temperatures T1 and T2. T1 > T2. The specific heat c does not depend on temperature. What is the maximal work which can be done from this system? I have to get equation for max work which includes c and temperatures. Homework Equations This seems to...

If our body temperature falls below 30 degrees C or so, it stops functioning properly and we die. 30 C seems still a rather warm temperature for normal chemical reactions to be able to occur, and in most environmental conditions inhabited by men it still represents a temperature gradient...

Hi all, I am analysing a 2D D-shaped Neo Hookean model in contact with a Rigid link. The details are in the input file attached. Can someone guide me on how to solve this issue?:headbang: Thanks, Bruce

Homework Statement Rigid body with one spring. Homework Equations Torque equations ( M=I * "alpha") The Attempt at a Solution So I think I can solve this problem but there is only one thing I do not understand. When I am writing my torque equation I would think that the weight of the bar...

I would like to know why the threshold voltage increases for an NMOS transistor when the voltage difference between the source and the body terminals is greater than 0. If, for example, the body terminal is connected to -1V and the source to 0V, holes from the p-substrate are attracted to this...

I read that a non rotating planet like Lubricon VI does not have equator because it does not rotate. So why only rotating planets have equator?

According to the documents I have read, Plank made two changes to Rayleigh-Jeans approach in order to produce an equation that matched the black-body radiation, experimental curves: 1) As a mathematical convenience he assumed that the oscillators in the walls of black-body cavity could only have...

< Mentor Note -- thread moved to HH from the technical physics forums, so no HH Template is shown >[/color] Does body fat percentage(s) include all brain fat percentage(s) and all body fat percentage(s)? (When responding to this post) If the answer is 100% yes etc, what is the lowest body fat...

Could someone explain to me how the kinetic energy of a body moving in a circle is like? I got tempted it stays constant as the speed is constant but that turned out to be false. I am interested in places where the body is at top, side and bottom and so on. So I'd like to also know what the KE...

Homework Statement I'm trying to do a little review of Lagrangian Mechanics through studying the two-body problem for a radial force. I have the Lagrangian of the system L=\frac{1}{2}m_1\dot{\vec{r_1}}^{2}+\frac{1}{2}m_2\dot{\vec{r_2}}^{2}-V(|{\vec{r_1}-\vec{r_2}}|) . Now I'm trying to find...

I know it follows a geodesic in space-time, but is it not being able to bend space-time itself, part of the definition? When I google i just find 'follows a geodesic in space-time'. I thought that it also should not bend space-time itself - but this isn't included in the definitions I've...

1. Relevant information This is a two-block-system on top of each other to the right side of a wall, both attached with springs that are also attached to the wall. A force is applied on the bottom block to the right direction, frictions occurred on both bottoms of the two blocks. Here is the...

I understand photon absorption/emission by electrons in atoms, that transition them between energy levels, producing sharp spectral lines. However, I am having difficulty understanding photon absorption/emission by the vibrational and rotational modes of molecules, with respect to black body...

Homework Statement In a uniform gravitational field, there is a uniform solid disk of of mass M and radius R. A point mass m is glued to the disk at a point that is at a distance a from the center of the disk. The disk rolls without slipping. Find the frequency of small oscillations about the...

Homework Statement A body is dropped from a height ##h## with an initial speed 0, reaches the ground with a velocity of 3 km/h. Another body of the same mass was dropped from the same height ##h## with an initial speed 4 km/h. The second body will reach the ground with what velocity ? Homework...

Homework Statement Determine the behavior of a drug in the bloodstream that enters the brain and the amount of this drug in the bloodstream that is delivered to the body at a given time as it decays. The amount of drug in the body is eliminated as described by an exponential decay half life...

So I'm upgrading my Physics Engine's Collision response system (don't worry, this is a pure physics question, no programming involved! Also don't worry about the time of collision, my collision detection system is separate and returns a time of collision for the response system to work with) and...

Homework Statement For the maximum angle for which you have data draw a free body diagram and explain how the forces add to give the resultant (net) force and show the calculations required to determine the acceleration. The lab was about using Galileo's inclined plane to measure acceleration...

Greetings. Well I do not have enough time to pose all of my questions and ideas I can get this thread started off. So let's get right into it. The teeth of a Beaver incorporate a comparatively high percentage of iron in their construction, making them very strong and orange hued. (Also made to...

Homework Statement Can i say a body has heat energy, like it kinetic or height energy? The next formula only shows the energy transfer in change of temperature Homework Equations Heat energy: ##E=c\cdot m\cdot\Delta t## The Attempt at a Solution I guess not, although it's obvious that the...

In the figure A has mass 4 kg. B and C are identical uniform discs, each of mass 2 kg. The string supporting A is ideal. Obtain the acceleration of A I have just one question, Why is pulley C undergoing translational motion ?, it should be rotational motion because it rotates about a fixed axis

Problem: I am having a bit of problem with the signs on the force balance with the constraining force. The system is: Attempt: I drew the FBD with the constraining force for the lumped mass: Then I tried to solve for the constraint force in terms of the spring and damper: For the...

hello! this is a question that iv been working on and can't seem to figure it out, i checked out the other two threads on this same question but they were of no help, anyway here it is: A wedge with mass M rests on a frictionless horizontal table top. A block with mass m is placed on the wedge...

Hi all! I would be interested in paints that show very high absorptivity/emissivity and that can withstand high temperatures (ideally above 1000°C) and used in vacuum. Do you have any commercial suggestions? Thank you!

Why does time dilation occur due to the velocity of a moving body, according to SR?

So, I've had several people insist that a dark colored object will radiate heat faster than an identical light colored body. I do not believe this is the case. We know that dark bodies ABSORB more short wave than light colors, and thus become hotter as a result...but that's not the issue...

Hi I have a problem in understanding the attached free body diagram problem. I have a shaft that is pivoted at the top. Below the pivot is a magnetic bearing with a radial stiffness of 2600N/mm. I've modeled this as a springs in parallel. Below the bearing is a motor with a radial stiffness of...

Inspired by the movie Interstellar which featured a planet orbiting a rotating supermassive black hole with an extremely high time dilation factor (slowed by a factor of 60,000 relative to observers far from the black hole), I was wondering if anyone knows of an equation for time dilation of...

If I know the temperatures of the two thermal reservoirs (one hot, one cold), the area of contact between each reservoir and the body, and the coefficients of conduction, it seems like I should be able to calculate the equilibrium temperature of the body, but I can't seem to figure out how.

So I am designing an apparatus to lift a 500g load up 500mm and I am trying to find reactions. I have filled in these values in my head with my own logic but I don't know how to do the maths and if I am right or not. I can do the initial position ok but it is the final position I am unsure of...

Suppose the box (stone, bullet..., $$m =1$$) is not moving upward because of a lift, but has been shot and has $$v = 20m/s$$ and $$KE = 200 J$$ Gravity is doing negative work and subtracting energy: $$F = -ma = 10 \cdot 1 = -10 N$$ We cannot use the palallelogram here as KE is not a force, how...

EDIT: "In what fashion are atoms or molecules added to a body, then attached, how exactly do they get replaced?" http://imgur.com/pmR8RB9 (I realize atoms are much smaller) Sorry for the crudity of my drawing but I think you get the general idea. I can't picture what happens? I believe they...

Homework Statement An m1 = 7.6 kg block and an m2 = 10.7 kg block, connected by a rope that passes over a frictionless peg, slide on frictionless incline. Find acceleration of boxes and tension of the rope. Homework Equations F=ma I'm not sure what else The Attempt at a Solution I'm really...

Homework Statement Not a homework or coursework question, but given the simplicity of the problem I feel that this is an appropriate subforum. Consider a person spinning a rock on a string above their head at a constant angular velocity, walking away from the observer at a constant linear...

Homework Statement The power delivered in narrow spectrum range near 10 µm from black body source with temperature 1000 K is 10 µW. Not Solved a) What power would be delivered in narrow spectrum range near 1 µm? Solved b) At what wavelength the power delivered takes its maximum? c) Find this...

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Homework Statement A large box containing your new computer sits on the bed of your pickup truck. You are stopped at a red light. The light turns green and you stomp on the gas and the truck accelerates. To your horror, the box starts to slide toward the back of the truck. (Assume that the...

[FONT=Book Antiqua]Lets say i have a rod (length = L) hinged at one end (A).It is initially at rest.Now if an impulse (J) acts on the other end (B),can i conserve the angular momentum about A(the hinge)? that is can i write: JL=Iw?(I=moment of inertia,w=angular velocity) this is what i saw in...

Homework Statement A large box containing your new computer sits on the bed of your pickup truck. You are stopped at a red light. The light turns green and you stomp on the gas and the truck accelerates. To your horror, the box starts to slide toward the back of the truck. (Assume that the...

Here is an unsettling question from a practice set that I've been working on today. Unsettling because the answer key contradicts my answer so I need a second thought. A pingpong ball and a golf ball are dropped in a vacuum chamber from the same height and at the same time. When they have...

Homework Statement A weight is attached to a wooden body with mass M=4kg lying on a horizontal surface. The coefficient of friction is μ=0.2. What is the mass m of the weight so that the wooden body is moving? Image: Homework Equations Equations of forces The Attempt at a Solution I tried...

I have a unbalanced body and have done for 10 plus years maybe longer. i think a combination of things has done it one i am from young age racket sports mad tennis and squash etc so my right hand side has always been stronger than my left. Also years ago when gym equipment when it was not...

i don't get it. why would a body with temperature give up photons? help please

What would happen if I was standing in the LHC and I was hit by a (one) proton traveling at 99.999991% the speed of light. Would the collision burn a hole in me? or would it simply be going so fast that it passes through me without interacting with the particles in my body?

Hi, it's been quite some years since I took some entry-level mechanics at uni, and my book is no longer with me, so I'm struggling a bit here. I'm making a very simple rigid body simulator just for fun, but the angular velocity is not working out right. I suspect I've forgotten something...

An heavy body near other body gives off gravitational waves at a higher rate than when it is away from any body. So, if there is only one body in the universe and nothing else.Will it give off the gravitational waves and it's mass will keep decreasing?

I was lately interested in learning how the human body weight changes through out the day. Like, how much weight (may be in just 10s of grams) is lost during sleeping, after bathing, after workout and like that. For that I would require a highly precise scale. But most commercially available...