Rotation Definition and 1000 Threads

Tell me- in general It is possible that -while writing torque equation about instant centre of rotation, we may get a pseudo torque term That is instant centre of rotation may have some angular acceleration Am I right ?

Ok, so I'll start off by saying this is NOT a homework problem, but it is a problem I'm having with a project I'm working on, and my supervisor has no clue as to why I'm getting the wrong results from a calculation I'm doing. So as you all reading this likely know, we can model the rotation...

Hello! I need to find the rotation matrix around a given vector v=(a,b,c), by and angle ##\theta##. I can find an orthonormal basis of the plane perpendicular to v but how can I compute the matrix from this? I think I can do it by brute force, rewriting the orthonormal basis rotated by...

That raised an interesting question in my mind. Wikipedia was not helpful providing answers. Surely we must have estimates of Earth rotation rate and tilt both pre and post impact with Theia. What are those numbers?

I wait for your thoughts on this topic... and maybe then I will give you a small surprise. edit: Ok, there was a misconception on my side that I want to clarify changing the original title by this one: If there are two planets, rotating one around the other, and only gravity is acting. Is it...

Can someone explain how the laser pointer is generating the rectangular patterns shown in this youtube video? I assume that there are just two diffraction gratings that are rotated relative to each other, but could someone explain mathematically how to predict what pattern is formed for...

Homework Statement I recently made a direct current motor with a battery and a magnet. Is it possible for the coil to move in both directions without changing the current or magnetic field? If so, why might the motor work better in one direction? Homework Equations F= BIL The Attempt at a...

Hey there! I would really appreciate if someone could help me with the following problem. I didn't find it anywhere (textbooks, web...). Not only currents but also magnetized bodies possesses magnetic moment. I know that if the magnetized body is at rest in a constant external magnetic field...

Homework Statement in this problem , it's not clear that whether the shortening of 1.5mm is for which rod , there are 3 rods in the diagram and forces applied at which part to cause the rotation ... ... Homework EquationsThe Attempt at a Solution Can somenoe explain about it ? if the forces...

Homework Statement The sun is a pretty typical star with a mass of 1.99x1030kg and a radius of 6.69x108 m. Since it isn't solid, it doesn't rotate uniformly, but has an average rotation rate of 1rev/25d. A star with a mass about about three times that of the Sun eventually explodes as a...

Homework Statement Consider a rod of length ##L## that is attached to a hinge making an angle ##\theta## with the horizontal. There is a force ##\vec{F}## acting vertically on the rod that creates constant angular velocity ##-\omega##. If there is fluid under the rod with constant density...

"The weight of an exercise book in picture A (where the centre of gravity is not on the axis of rotation) rotates so it moves towards the second position in picture B (where the axis of rotation goes through the centre of gravity). Explain why." I don't believe any equations are necessary for...

I'm familiar with galactic rotational curves and there are plenty of graphs depicting such curves, but I'm interested in the rotation curves of entire galactic clusters at the moment and I'm not too good with sifting through what shows up in the search engines. (not a physicist, just a...

Homework Statement There is a object traveling at 0,2m/s with a mass of 75,000kg. The object impacts a fixed point at a distance of 3.5m from its center of gravity (COG) and rotates around this point. What is the reaction force at the point of rotation? Homework Equations I think it is...

I found the following problem on the 2009 F = ma exam. 24. A uniform rectangular wood block of mass M, with length b and height a, rests on an incline. The incline and the wood block have a coefficient of static friction, μs. The incline is moved upwards from an angle of zero through an angle...

a disc of mass m and radius r rolls down a slope of incline tan^-1 3/4. the slope is rough enough to prevent slipping. the disc travels from rest a distance of s metres straight down the slope. (i) show that the linear acceleration of the disc is 2/5 g. what i did was i first revolved the forces...

Homework Statement Imagine a uniform, symmetric rod, free to rotate around an axis going into the computer screen through the center of the rod. Now say that we start off the rod so that it is not horizontal or vertical, but somewhere in between. My intuition tells me that the rod will start...

**I am an extreme amateur when it comes to physics, so please forgive me if I use the wrong terminology or my description is incomplete** My washing machine always seems to get out of balance and "walk" across the room during the spin cycle, which led me to think up the following scenario...

Hi,I wanted to know what exactly the free rotation of bonds in alkene means in the cis-trans isomerism?[

Dear All, I have a monoclinic cell with a=18.7,b=3.55,c=9.069 and beta=134 degrees, angle between a and c. Now I need to make the c axis parallel to z axis for surface calculations, ie to introduce a vacuum. What is the rotation matrix that would do this?? Thank you.

Homework Statement Where are the instantaneous centers of rotation? Instantaneous center of rotation = 1. Velocity is 0 in this point. 2. This can be also a point where 2 parts "touch" each other and have the same velocity in this point. Homework Equations / The Attempt at a Solution...

I would like to add an interactive 3-D rotation to my web page and I was wondering if someone could suggest what I could look into. I understand U3D is a common format for doing this in PDF files. Is that the format I would need to use in a web page? Would I need a Java applet to set this up...

If an object say a cylindrical body is gripped in a frame and that frame is being rotated by some mechanism, what forces should be considered on the gripped object in order to know the necessary force required for a proper grip?

Homework Statement Ans : b) Homework EquationsThe Attempt at a Solution [/B] Assuming wind mass moves towards east at the equator , as it moves up it retains its linear speed . At higher latitudes the angular speed of Earth is same but linear speed at the surface of Earth decreases . So ...

I am currently reading Goldstein's Classical mechanics and come on to this problem. Let q1,q2,...,qn be generalized coordinates of a holonomic system and T its kinetic energy. qk correspondes to a translation of the entire system and qj a rotation of the entire system around some axis, then...

1. The problem statement: Consider a solid sphere and a hollow sphere, of equal mass M and equal radius R ,at rest on top of an incline . If there is no slipping which will reach the bottom faster. 2. Homework Equations : acm = Fext/M (cm= centre of mass) angular acceleration= torqueext/ I ( I...

Homework Statement for the τx'y' , i use the formula of -0.5(σx - σy)sin2θ + τxycos2θ , i found the ans is -41.3 rather than positive 41.3 , which part of my working is wrong? or I misunderstood something? Homework EquationsThe Attempt at a Solution

Homework Statement A solid cylinder is attached by a rope on its center.It has mass of 5kg and is lying on a table.The other end of the rope is a block of mass m2 which is not on the table .if the coeficient of friction between cylinder and table is 0.2.Find the maximum mass 2 so that the...

The main question is in the title. 1.I have wondered if a regular pencil would precess and rotate stable for multiple seconds if spun fast enough. [Coins, plates, bowls and similarly shaped objects can rotate in a stable way for extended periods of time. And a lot of other household objects...

Which galaxy has the largest angular momentum of all galaxies observed? What does its rotation curve look like? Which galaxy has the smallest angular momentum of all galaxies observed? What does its rotation curve look like? Which two galaxies are closest to one another? What do the rotation...

I have posted this question earlier but I think it was ill-stated. I try to give it in a simpler fashion in this thread. In the problem it is stated that there a rotation around the x-axis of a (stereographic) sphere is given by $$\delta \phi = \cot \phi \cot \theta \delta \theta$$ where...

I am a high school student experimenting with the Verdet constant of materials and how it affects the polarization of light in magneto-rotation. I have trouble acquiring the proper materials for this experiment. Here is what I have so far: -AC/DC Power Supply -Gaussmeter -Optical laser under...

What would happen if an aircraft was fast enough to match the speed of the rotation of the Earth and it decided to fly against it matching that exact speed (earth's rotation)? I would imagine it would look like Earth was speeding up but would there be any other physical effects on the aircraft...

Homework Statement A light string is passed over a pulley and two masses m1 and m2 are suspended from the two free ends. The pulley is a uniform circular disc of mass M. Find the linear acceleration of the two masses. Friction may be neglected. Homework Equations I through center of the disc =...

As far as I understand it, a nebula initially tends to have a small amount of rotation (on average) and then as it collapses under its own gravity this rotation increases significantly due to conservation of angular momentum (assuming that there is no external torque,right?!). What I'm unsure...

If a planet is in retrograde orbit, what direction would it rotate to also have retrograde rotation?

Homework Statement Is the conservation of angular momentum theorem right for instantaneous center rotation? That: If all total momen of force is zero. The angular momentum will not change If right, prove that. Homework Equations All equations of rotational motion The Attempt at a Solution I...

Hello, i need a little help. Did someone have an idea how to prove this? Thanks in advance. Be ##\Phi## an direct isometry of the euclidean Space ##\mathbb{R}^3## with ##\Phi (\begin{pmatrix} 2\\0 \\1 \end{pmatrix})##=##\begin{pmatrix} 2\\1 \\0 \end{pmatrix}## and ##\Phi (\begin{pmatrix}...

Homework Statement A massless rod of length L connects three iron masses. If the first mass (at x=0) has a mass of 1.90 kg and the second mass (at x=L) has a mass of 8.77 kg and the third mass (located at the center of mass of the system) has a mass of 148 kg, what is the moment of inertia I...

I have recently read a paper called "Engineering of Gravity and Time" for an undergraduate student. It contains a theory of gravity and time depending on rotation. Well.., I think it looks quiet percussive. However, fairly, it contains some worthwhile ideas, especially it answers some elementary...

So I THINK I understand that the tidal bulge is resting slightly in front of the moon because of the Earths rotation and the moons gravity, it pulls the moon 'forward' a little adding energy to the moons orbit and expanding it, what I do not understand is why the Earths rotation is slowing. I...

First, I'd like to say I apologize if my formatting is off! I am trying to figure out how to do all of this on here, so please bear with me! So I was watching this video on spherical coordinates via a rotation matrix: and in the end, he gets: x = \rho * sin(\theta) * sin(\phi) y = \rho*...

Does anyone know of galactic rotation data (any galaxy) of the following form: For simplicity assume an [x y z] coordinate system with the origin in the center of the galaxy and [x y] representing the plane of rotation. At any point [x y z] there is a corresponding velocity vector [vx vy vz]...

In special relativity, the electromagnetic field is represented by the tensor $$F^{\mu\nu} = \begin{pmatrix}0 & -E_{x} & -E_{y} & -E_{z}\\ E_{x} & 0 & -B_{z} & B_{y}\\ E_{y} & B_{z} & 0 & -B_{x}\\ E_{z} & -B_{y} & B_{x} & 0 \end{pmatrix}$$ which is an anti-symmetric matrix. Recalling the...

Homework Statement [/B] In a set of axes where the z axis is the axis of rotation of a finite rotation, the rotation matrix is given by ## \left[ \begin{array}{lcr} &\cos\phi \ \ \ &\sin\phi \ \ \ &0 \\ & -\sin\phi \ \ \ &\cos\phi \ \ \ &0 \\ &0 \ \ \ &0 \ \ \ &1 \end{array} \right]##...

Homework Statement The rope doesn't slide on the pulley, it's mass is negligible and it doesn't stretch .The pulley's moment of inertia is 0.00300 kg * m^2 with a radius of 10 cm. As the first mass goes down the rope's friction generates a moment of force of 0.150 N*m opposed to the angular...

Hi, i'm hoping to get a bit of assistance with stopping a nut from coming un-done if possible. I have an application using a load cell which is being inserted into metal rod, and then pulled under tension. The load cell is inserted into a hole drilled in the rod and screwed in at the bottom...

So I am having trouble with this one, I was wondering if an object could have more than one axis of rotation. More than one axis of rotation goes against what I think is possible until I thought about a coin, at which point I was stumped, if the coin was rotating in the way a coin rotates when...

http://mathhelpboards.com/attachment.php?attachmentid=5579&stc=1 W9.3.8 Let $S$ be the region of the xy-plane bounded above by the curve $x^{3} y = 64$ below by the line $y = 1$, on the left by the line $x = 2$, and on the right by the line $x = 4$. Find the volume of the solid obtained by...

Homework Statement A ball rolls down an incline plane without slipping. What is the ratio of its angular velocity at h/3 to its angular velocity at 2h/3? 1) 1:2 2) 1:sqrt(2) 3) 1:1 4) sqrt(2):1 5) 2:1 Homework Equations Conservation of energy with provisions for rotational and...