# All Questions

135 views

### Is it sure that gravitons are massless bosons? [duplicate]

Possible Duplicate: “Speed” of Gravity and Speed of Light I'm wondering if gravitational waves have the same speed of light? They must if gravity is mediated by a graviton spin ...
551 views

### Hydraulic System in a Simulation

A simulation project we are on, we have a machine with hydraulics that are powered (They don't just look like they move something, they are the only thing moving/turning/lifting something) - However, ...
91 views

### References for circular restricted 3 body problem?

Does anyone know of any good references for the CR3BP -- the circular restricted 3 body problem? Emphasizing on real-life applications, and interpretation of the numerical solutions? Thank you. There ...
2k views

### Question Based On Units And Measurements Involving Lengths [duplicate]

The below is the sixth question of the very first chapter from halliday and resnicks fundamentals of physics text,which i'am not able to comprehend. Harward Bridge,which connects MIT with its ...
453 views

### Special Relativity - Relativistic Dynamics

I've been wrestling with this problem but to no avail. I'm hoping that someone here can give me a little nod in the right direction. Problem statement: A thrust-beam space vehicle works bearing a ...
161 views

### Which bonds are the cross-links and which are secondary bonds (in elastomers)? [closed]

Elastomeres are "defined" as: "linear-chain polymers with widely spaced cross-links attaching each molecule to its neighbours" Now I found sentences (talking about glass transition): "This means ...
1k views

### How to find acceleration given position and velocity? [closed]

Sorry for this very simple question but I am still very new to the laws of motion. I am dealing with 2-dimensional vectors in my programming environment and I'm following these slides to learn about ...
85 views

### Springs yet again, this time with a picture. Infinite displacement, makes no sense [duplicate]

Possible Duplicate: How could this damped oscillator ever go to infinity? Or negative infinity for that matter? Consider this ! Where I purposely drew the right arrow bigger than the left ...
281 views

### Question about interaction between three objects

I have been thinking of Newton (insert bad words because of frustration) laws for hours and hours today, and I'm not going anywhere. I'm going insane! So, I made up this question. Object A | ...
92 views

### Can a wave propagate in an elastic fluid in the absence of volume forces?

A motion (wave) $\mathbf{x}: \mathcal{B}_0 \times [t_0,t_1] \to \mathcal{E}:$ such that $q-o = \mathbf{x}(p,t)=(p-o)+\mathbf{a}_0 cos(\mathbf{k}_0\cdot(p-o) - \omega_0 t)$ can propagate in an elastic ...
2k views

### How to find speed from Newton's law?

I have a question about Newton's law. The question says block A(mass 2.25kg) rests on a tabletop. It is connected by a horizontal cord passing over a light, friction less pulley to hanging block ...
1k views

### Eliminating IR light reflection perceived by a steep viewing angle

I am having a problem with reflection on an acrylic surface, in the IR part of the spectrum. This reflection is interfering with an algorithm that looks at objects, as it makes two show up when only ...
53 views

### How can I figure out how many kWh's are in a battery using the mAh's and voltage. [duplicate]

Possible Duplicate: Relating milliampere-hours to watt-hours for batteries How can I figure out how many kWh's are in a battery using the mAh's and voltage. Some batteries only list mAh's ...
213 views

### What is the electric field part of an EM wave? Radiation field or the induction field?

Look at this image: I wonder if the electric field is from the induction field from a vibrating electron or the radiation field? If it is from the radiation field, as I suppose, than can someone ...
51 views

### Problem on nuclear physics radioactivity [duplicate]

Possible Duplicate: How do we know that C14 decay is exponential and not linear? Please help me solving this problem. Find the half life period of uranium-238,if one gram of it emits ...
821 views

### Increase of threshold current by temperature in a laser diode

I read somewhere that if we increase the temperature of the material in a laser diode the threshold current for lasing also increases. Can someone explain to me why is this happening? What is the ...
2k views

### Force and Laws of Motion [closed]

While catching a fast moving cricket ball, why do fielders gradually pull back their hands backwards with the moving ball? Please advice which among the following is the correct answer. If both are ...
101 views

### Book for learning about constructing correct physical modeling [duplicate]

Possible Duplicate: List of good classical physics books I know physics. At least I thought so until I tried to make a model of the system of scales by myself. It was confusing. For example ...
1k views

### As ISA Practical - Resistors in Parallel [duplicate]

Possible Duplicate: Current against the inverse of resistance graph, I = V/R +c How would you set up a circuit with a fixed resistor in parallel with a variable one. We are told to measure ...
162 views

### Nonablianity of Wilczek Zee Potential

Consider a hamiltonian with degeneracies of energy in parameter space $(R)$.Now the Geometric phase(Wilczek Zee Potential) will acquire a non abelian nature. To prove the non abelian nature of Wilczek ...
42 views

### Why has the ether been disregarded as a valid medium through which light can propagate? [duplicate]

Possible Duplicate: Ether theory acceptance Although the Einstein's theory of relativity seemed to make the concept of an ether obsolete, did it necessarily invalidate it? Are there any ...
347 views

### What is the name of the molecule HCCO? [closed]

I have a very hard time finding information about $HCCO$. I don't even know what it's name is. I'd like to know what its main features are, where it shows up and/or what it's used for?
50 views

### Does mass affects accelleration of an object in a sloapy movement? [duplicate]

Possible Duplicate: Would a light or a heavy ball roll fastest down a slope? Is there a change of the accelleration of an object moving on a sloapy plane if the mass is changed?
179 views

### Finding time in ballistic problem

The problem is like this: A bullet with mass 15g moving at a speed of 425 m/s is brought to a stop in 3.5 cm in a block of wood. Find the force on the bullet, assuming that it is constant. ...
197 views

### Determine the tensor of contraint and deformation of a cube under compression

We have a cube under compression with dimension l1*l2*l3, is put between 2 rigid plates in the axis 1 (two plates block the deformation of the cube in thí axis), the cube is also put on a rigid plate, ...
190 views

### How do I tackle this problem WITHOUT focusing the whole system as a “single mass”?

Problem/Solution ! ! In the third FBD, they made the whole system as one object. What happens if I don't want to do that? What if I jsut apply Newton's second Law to the mass M? I tried it out but ...
185 views

### semiclassical approximation for the exponential sum (partition function)

for any real and positive 's' and in the sense of semiclassical approximation is this valid ?? $\sum_{n}exp(-sE_{n})\sim \iint_{C}dxdpe^{-s(p^{2}+V(x))}$ valid for every 's' here simply both the ...
187 views

### Is reflection just a particular case of scattering?

I was talking to a colleague about optical scattering from a metallic nanoparticle, and we had a very simple doubt. If you have a particle that's small compared to the illuminated area, you can use ...
8k views

### How does evaporation affect the temperature of the air?

A wet object or a volume of water will decrease in temperature due to the effect of evaporation. We understand this to be because of the molecular kinetics, where the faster water molecules escape ...
897 views

### Basic Free Fall Problem [closed]

So I am trying to remember my childhood doing some Physics problems, but seems that I forgot almost everything. But it's not a big thing... that's why I'm training! My problem is pretty basic ...
149 views

### How long until “final totality”? [closed]

It is given that the angular size of the Sun as viewed from Earth is $0.533^\circ$, the distance of the Moon from Earth at perigee is $3.633\times 10^5$ km, and the mean radius of the Moon is $1737.1$ ...
162 views

### 2 streams going into an engine and 2 come out. Find the enthalpy?

Problem: Steam supply to an engine is made of two streams that mix before entering the engine. Stream 1 flows at a $.01\frac{kg}{s}$ with an enthalpy of $2952\frac{kJ}{kg}$ and a velocity of ...
135 views

### More data points or more averages?

Perhaps an elementary questions. Given a time limited measurement situation, would it be better for one to measure more averages or more data points? More averages will increase the SNR by ...
508 views

### Finding work done by rotational force?

A disk with a rotational inertia of 5.0 kg·m2 and a radius of 0.25 m rotates on a fixed axis perpendicular to the disk and through its center. A force of 2.0 N is applied tangentially to the ...
1k views

### Does power from a resistor perform work or heat transfer?

Let's say I have a cylindrical piston filled with air and fitted with an electrical resistor. The resistor has a current going across it and a voltage for a certain amount of time. My system would be ...
406 views

### What final states can proton-proton collision generate?

What final states can proton-proton collision generate? Where to find listing of possible final states of a particle interaction, for example proton colliding with proton?
93 views

### Literature request for books / review papers on gravitation, gauge theories and related mathematics [duplicate]

Similar to this reference, are there more such references / works [including textbooks] available in the literature? (A list would be greatly welcomed and appreciated.) With great appreciation.
744 views

### Applying a force on a rigid body on a certain point

I have a rigid body with an origin point (at the center of mass). I want to apply a force on a certain point. So what is the force applied to the origin of this rigid body? Description image: ...
57 views

### If Earth Were Filled with a Compressible Fluid and Spun Really Fast, What Hollow Would Form? [duplicate]

Possible Duplicate: What nonlinear deformations will a fast rotating planet exhibit? This is really a basic physics question that I wanted to check myself on because I'm not entirely sure ...
2k views

### Is the static gauge pressure of a free jet always atmospheric?

Let's say I have a free jet of air leaving a pipe into the atmosphere. I know that the static gauge pressure at the pipe exit is equal to the atmospheric. But what about the static gauge pressure 10 ...
349 views

### Clarification of equilibrium expression for upside down can in water

Let's say I initially have an open, empty, soda can. I then turn it over and lower it into a bowl of water, and then release it. Obviously water rises to some level in the cup and then there is air at ...
1k views

### Simple Harmonic Motion Question [closed]

I have two formulae: Displacement = Amplitude * Cos(Angular Frequency * Time) Velocity = - Amplitude * Angular Frequency * Sin(Angular Frequency * Time) OR $x = Acos(wt)$ $v = -A.w.sin(wt)$ And ...
84 views

### When will the moon fall down? [duplicate]

Possible Duplicate: Are tidal power plants slowing down Earth's rotation? I've heard that there are turbines converting energy from tidal waves. Tidal waves are created by the moon's ...
514 views

### Phase space of a discrete dynamical system

Suppose a dynamical system of one variable $x$ with discrete time-steps. I've seen in some papers a type of graph in which $x(n+1)$ is plotted versus $x(n)$. My questions are : 1/ Can this be ...
311 views

### Moving charge as a magnet, is the sign relative?

A thought experiment: Suppose we are moving in a spacecraft (A), carrying an excess of electrons on spaceship surface, but we can't go outside to measure it, and it's moving at constant speed $v$, ...
1k views

### How does the X-Y mode of an oscilloscope work?

I recently used an oscilloscope in X-Y mode to draw the phase ellipse of two voltages. I then used the formula $\phi = \arcsin(2y/B)$ where $y$ is the value of the ellipse at $x = 0$ and $B$ is the ...
624 views

### Physics tension question [closed]

Two blocks are pulled across a frictionless surface by a $240\ N$ force, as shown in the diagram below: $60\ kg$ - - - cord - - - $20\ kg$ → $240\ N$. If the blocks are accelerating at $3\ m/s^2$ what ...
66 views

### How to calculate 2D soft-body Physics [duplicate]

Possible Duplicate: 2d soft body physics mathematics The definition of rigid body in Box2d is A chunk of matter that is so strong that the distance between any two bits of matter on ...
172 views

### Remnant of a supernova [duplicate]

i explain better A supernova remnant is the structure resulting from the explosion of a giant star . The supernova remnant is surrounded by an expanding shock wave that is formed from material ...
114 views

### Faster than light communication [duplicate]

Possible Duplicate: Is it possible for information to be transmitted faster than light? Suppose you have a very long rod, both ends are in space and the rod is 100 light years long. If you ...

15 30 50 per page