Rotating Definition and 1000 Threads

Imagine two frames one inertial (x,y,z) and the other rotating (x',y',z'), their origins are always coincident. The rotating frame is rotating as seen from the inertial frame with a time-dependent angular velocity ##\boldsymbol{\Omega}(t)=(\Omega_x(t),\Omega_y(t),\Omega_z(t))##. In the rotating...

Homework Statement There is some current in the bottom coil. The question asks which would not be able to light the lightbulb - rotating the insulating handle 90 degrees - increasing resistance of variable resistor -reducing resistance of variable resistor - moving the insulating handle...

1. A weightless rod carries towards of masses M and M. The roads Hinge Joint to vertical axis OO', which rotates with an angular velocity ω. Determine the angle φ formed by the rod and there vertical. The attempt at a solution If I am not wrong, the two ways to ensure equilibrium are...

##\ \ \ \ \ ##Calculate the 4 momentum of a rotating rod. We divide it into 4 parts. The part 1 is the work of predecessors. ##\ \ \ \ \ ##In Special relativity, the motion of rod AB (which is an object in non inertial motion) can be described in an inertial reference frame and the motion of rod...

Homework Statement [/B] A thin cylindrical rod with the length of L = 24.0 cm and the mass m = 1.20 kg has a cylindrical disc attached to the other end as shown by the figure. The cylindrical disc has the radius R = 8.00 cm and the mass M 2.00 kg. The arrangement is originally straight up...

Hi There, Long time reader, first time poster.. I hope someone out there can help me. I'm designing an add-on to an existing piece of equipment and I'm unsure of how to calculate the resultant force output from a hydraulic cylinder. On a straight push, the chosen hydraulic cylinder has an...

Homework Statement A solid uniform disk of mass 21.0 kg and radius 85.0 cm is at rest flat on a frictionless surface A string is wrapped around the rim of the disk and a constant force of 35.0 N is applied to the string. The string does not slip on the rim. 1- When the disk has moved a...

I am working on a design where I have a block which has a cap assembly fitted to it - see images attached. The cap assembly is constructed of: - Main body with two holes through (flowing water in and out) - Locking ring with a threaded outside, grooves for tightening by hand and two o-rings...

Hey all, I have a question that I am trying to figure out. It is more qualitative than anything, but I am concerned with the concepts that are involved in a scenario like this. Suppose we have a rotating disk with the plane of the disk perpendicular to the z-axis. Now we send a particle upward...

What is the largest possible Rotating wheel space station possible to be constructed with current materials? and what would be the population it would support. also formulas used for calculation.would be useful. Could constructing cylindrical space elevators support more population,

Homework Statement A square circuit of resistance R=20Ω and side ℓ = 0,2 m spins 100 times per second around an horizontal axis that splits it in two. There is an uniform magnetic field B=1T perpendicular to the position ocupied by the circuit at t=0s. Calculate (1) the magnetic flux, (2) the...

Hi, I am trying to gain insight into using stationary vs. rotating coordinate frames for natural frequency calculations. I have seen many FE codes suggest that critical frequencies can be calculated differently in rotating and inertial frames, so i wanted to do a 1D calc to see for myself how...

Homework Statement [/B]Homework EquationsThe Attempt at a Solution Sir if the pendulum is given an angular velocity about the -he z axis then whether eq 1 is right for balancing force and I have a contradict regarding eq 2 and eq 3[/B]

Homework Statement A circular hoop of radius R rotates with angular frequency ω about a vertical axis coincident with its diameter. A bead of mass m slides frictionlessly under gravity on the hoop. Let θ be the bead’s angular position relative to the vertical (so that θ = 0 corresponds to the...

Consider that we have a magnet and a magnetometer (a fluxgate magnetometer with a single coil), standing still as shown in fig 1. In fig 1, the magnetic field measured at the axis z1 of the magnetometer coil is B1. But if everything (magnet, magnetometer and the axes) was rotating together...

I have the metric: $$ds^2 = −(1 − \Omega^2 (x^2 + y^2 ))dt^2 + 2\Omega(ydx − xdy)dt + dx^2 + dy^2 + dz^2$$ In order to calculate the Christoffel symbol I need to compute the inverse matrix of the above, is there some computational shortcut besides the joke:" using mathematica"? Thanks!

Homework Statement Consider the Godel Metric in spherical coordinates as on page 6 here; ds^2=4a^2\left[-dt^2+dr^2+dz^2-(\sinh^{4}(r)-\sinh^{2}(r))d\phi^2+2\sqrt{2}\sinh^{2}(r)dt d\phi)\right] This is a solution to Einstein's Equations if we have ##a=\frac{1}{2\sqrt{2\pi\rho}}## and ##\Lambda...

The idea is that, if we take the rotating frame of the fluid-planet so that it is at rest, then the sum of gravity and the centrifugal force must be perpendicular to the surface. Take the planet to be rotating about the y-axis at a rate ω. By symmetry we only need to work in 2 dimensions. So...

Homework Statement Homework Equations f=ma v^2/r The Attempt at a Solution I am confused about this question because i am not given an angle theta for the normal force on the ball. My x component has only the normal force, my y component has only the gravitational force. I set my y...

Homework Statement Homework EquationsThe Attempt at a Solution I am considering the two rods separately .Considering QP alone EMF induced will be (1/2)Bωl2 with Q at higher potential . Considering QR alone EMF induced will be (1/2)Bωl2 with Q at higher potential . This gives zero potential...

This dumb video is making the rounds of the dumb. Apparently, it's not enough to promote that water goes down the drain in different directions in different hemispheres, but now apparently, you only need to go 10m to either side of the equator. I'm thinking about making my own video showing...

What would spacetime look like near a black hole that was rotating at its extremal speed and had a ring of matter orbiting it at ultra-relativistic speeds (just outside the photon sphere), such that the ring was orbiting in the same direction as the black hole’s rotation? The ring would add to...

Homework Statement Homework Equations F=ma τ = Iα = rF v=rω, a=rα L = Iω Center of Mass/Moment of intertia equations The Attempt at a Solution [/B] So right now I've tried to model the force acting on the ring as it goes around the peg, but I think centripetal force is involved and I'm not...

Homework Statement Imagine that you had two polarizing films and were holding them one on top of the other. What would the effect of rotating the two polarizing films, with respect to one another, be? Explain what would be seen, and why.[/B] Homework Equations n/a The Attempt at a SolutionThe...

Hi! I'd like to calculate the rotating magnetic field in a stator The stator is the attached picture. What I understand is the more current = the more rmf, so is there any equation / formula to calculate the rmf as a result of current? Thank you

I know that rotation can cause there to be artificial gravity. But I was thinking of making a floor plan that is all horizontal with the generation ship having a rocket shape and with it being longer than it is wide and wider than it is tall. So I was thinking of giant centrifuges on every...

Homework Statement A cylinder of mass M and radius R is resting on a horizontal platform (which is parallel to the x-y plane) with its axis along the y- axis and free to rotate about its axis. The platform is given a motion in the x-direction given by x= Acos(ωt). There is no slipping between...

(sorry if posting in the wrong place) I am looking for some mirror setup where rotation one or more elements in the mirror setup will allow to shift the beam along its axis. Two mirrors in a galvanometer scanner type setup work well for controlling the angle of the beam. Rotating risley...

Hello! I'm currently working on a project that will utilize the phenomena of eddy currents to apply a braking force to a rotating disk. Some background on this project: My team was tasked to create a physical therapy training device to train patients in wheelchair propulsion at resistances lower...

And if so, how much? Should the radius be thought of as zero, an infinitesimal, or as the Planck length? v2/r = ω2r If its zero, then you immediately run into a problem when trying to calculate it with linear velocity. v2/r = ar v2/0 = undefined OR ω2r = ar ω20 = 0 Which would mean that...

Homework Statement An ant clings to the outside edge of the tire of an exercise bicycle. When you start pedaling, the an't speed increases from ) to 10 m/s in 2.6 s. The wheel's rotational acceleration is 13 rad/s^s. Determine the average tangential acceleration of the tire. Homework...

This is question that can't really get a precise answer without significant modeling or experimentation, but I'm wondering what folks' intuition might be on an answer to the following setup + question: Suppose there is a steel tank made of steel pipe with walls about 0.25 cm thick, internal...

Hello Everyone.. Consider a small moving mass following a spiral path away from center and the body is rotating about its center as well. At some time the body impacts with a relatively bigger mass and transfers some of its energy to it. If we want to make an equivalent system with only linear...

Hi all, I was reviewing the Coriolis effect and I came across the attached explanatory image (from the Italian version of a book on physics by Cutnell, Johnson, Young and Stadler). The idea is the following. two guys are facing each other on a rotating carousel; one of the guys on the throws...

Suppose we have a rotating frictionless disk and there is a rotating observer on the center of it. Furthermore, suppose a very small ball on the disk's edge. Now we clearly know that the ball is not moving but the rotating observer sees the ball following a circular path with an angular velocity...

Homework Statement A thin stick of mass M = 3.9 kg and length L = 1.8 m is hinged at the top. A piece of clay, mass m = 0.3 kg and velocity V = 2.9 m/s hits the stick a distance x = 1.60 m from the hinge and sticks to it. What is the angular velocity of the stick immediately after the...

Homework Statement If the motor M exerts a constant force of P = 300 N on the cable wrapped around the reels outer rim, determine the velocity of the 50 kg cylinder after it has traveled a distance 2 m. Initially the system is at rest. The reel has mass 25 kg, and the radius of gyration about...

I am reading about Kerr black holes and non rotating black holes. But I am unable to understand what decides whether the black hole will not rotate or rotate. And if No Hair theorem suggests, we can know about a black hole through its angular momentum, what implications does zero angular...

Hi everyone ! i want to find the equivalent mass of a car rotating parts and i came across this site which provides some cars formula : http://www.thecartech.com/subjects/auto_eng/car_performance_formulas.htm So far i understand almost everything until i get to the part where inertia resistance...

Homework Statement Homework EquationsThe Attempt at a Solution The option (a) says that the 1st coin remains at its earlier position. Due to gravitational force, the 1st coin falls down, hence option (a) is wrong. I don’t understand the difference between option (B) and (C). In my opinion...

Homework Statement A uniform rod (mass = 5.0 kg, length = 0.3 m; the rotational inertia of the rod relative to the axis through its centre of mass is I = (1/12) ML^2 ) is free to rotate about a frictionless pivot at one end. The rod is released from rest in the horizontal position. What is the...

Just trying to understand how efficient RDE's are thermodynamically based on a 2016 paper from Bulat and Volkov titled "Detonation Jet Engine. Part 1 – Thermodynamic Cycle" and a 2013 paper by Nordeen et. al. titled "Thermodynamic Model of a Rotating Detonation Engine": Based on these papers...

Does a rotating conductor generate an electrical potential due to charges "feeling" a centrifugal force?

Homework Statement Another question with the same idea, These questions bother me a lot. Hopefully you can help me figure why they solve it this way. https://image.prntscr.com/image/aRnAD33ES2mML5JBwQBQvQ.png it said in the question that U = 0.6 without saying if it is static or kinetic...

Homework Statement A uniform rod (length = 2.4 m) of negligible mass has a 1.0-kg point mass attached to one end and a 2.0-kg point mass attached to the other end. The rod is mounted to rotate freely about a horizontal axis that is perpendicular to the rod and that passes through a point 1.0...

Hi everyone, sorry for bothering y'all again but here is another problem that I'm struggling with! This is the question and the professor's solution guide: When I solve the problem, I always end up getting 7.67 rad/s instead of 3.83 rad/s. My understanding of the solution is this: This is...

Homework Statement A rotating magnetic dipole is built by two oscillating magnetic dipole moments, one along the y-axis and one along the x-axis. Find the vector potential at a point: (0, 0, ##z_0##) along the z-axis. Then find the magnetic field at ##z_0## . As the magnetic field is a function...

Homework Statement Sorry for the bad resolution on the image but I will clear the variables out. The friction act on points A and B, Us = 0.2, W = 900 and there is a force P to the right The question is: Find the force P that makes the weight move downward with a constant velocity Homework...

Hi! I am currently working on a project that includes rotating a water-filled container. The container is NOT spinning about its vertical axis, but about the vertical axis of the rotating disc. I am aware that the surface shape of water in a rotating bucket takes the shape of a parabola when it...

I need help understanding what kind of problem this is at all, since I'm really lost. I'm missing the specific topic name (I called the topic "circular motion" because it's got something to do with it, but maybe it has a more specific sub-topic name), probably missing key formulas, and generally...