Rotating Definition and 1000 Threads

Homework Statement Using disks or washers, find the volume of the solid obtained by rotating the region bounded by the curves y = sec(x), y = 1, x = 1, x = -1 on the x-axis. The Attempt at a Solution This should be ridiculously easy but apparently my answer is wrong?! To calculate the...

Is the energy of a rotating cylindrical spacecraft conserved when a point-like astronaut climbs up a spoke connecting the walls with the center of the cylinder? If so, when I calculate the fractional change in apparent gravity at the walls when the astronaut reaches the middle I get different...

Solving "poisson's equation" slowly rotating spherical shell of mass Homework Statement We have that \partial ^{\alpha}\partial _{\alpha}\bar{\gamma _{0\mu}} = -16\pi T_{0\mu} which is very similar to Poisson's equation if we treat each component of the metric tensor as a scalar field (the...

Homework Statement The hollow tube is pivoted about a horizontal axis through point O and is made to rotate in the vertical plane with a constant counterclockwise angular velocity θ'=3rad/s. If a 0.1-kg-particle is sliding in the tube toward O with a velocity of 1.2 m/s relative to the tube...

Homework Statement Q: A rod of length l rotates with a uniform angular velocity ω about the axis passing through its center and perpendicular to its length. A uniform magnetic field B exists with its direction normal to the plane of rotation. The e.m.f. induced between the center and anyone...

Homework Statement A metal rod (1/sqrt(pi)) m long rotates about one of its ends in a plane perpendicular to magnetic induction of 5*10^-3 T. Calculate the number of revolutions made by the rod if EMF induced between the ends of the rod is 1.5 mV. I have been thinking about this problem for...

Homework Statement An electric generator consists of a rectangular coil of wire rotating about its longitudinal axis which is perpendicular to a magnetic field of B = 1.70 × 10-2 T. The coil measures 13.00 cm by 19.00 cm and 200.00 turns of wire. The ends of the wire are connected to an...

Galileo tried to convince church leaders of the correctness of the Copernican Theory. He had difficulties because the leading thinkers of his day couldn't believe in the rotation of the Earth on its axis. They thought that a spinning Earth would be easily felt and the Earth must be stationary...

Pulsars -- Rotating neutron star produces EM radiation? Hello, If a neutron star is composed of neutrons, which do not carry any electric charge then how it's rotation produces pulsars which are electromagnetic radiation? Thanks.

"Find the area of the surface of the curve obtained by rotating the.." 1. Find the area of the surface obtained by rotating the curve y= 1+5x^2 from x=0 to x=5 about the y-axis. 2. I thought to find surface area, we would need to use this formula: SA= ∫2\pi(f(x))√(1 + (f'(x))2)]dx...

Homework Statement Region: f(x) = 2 sin x on the interval [0, π]. Find the volume of the 3D solid obtained by rotating this region about the dashed line y = −1. Homework Equations Integration of pi∫(2sin(x) + 1)^2 dx The Attempt at a Solution...

I wanted to solve the problem of a cone rotating on its side over a table, around an axis that pass through it's apex, like in the figure. What I want to find is the angular speed ω, the spin of the solid, such that the cone "stands" over it's apex. I don't know how to set the condition...

Homework Statement Find the volume of the solid generated by rotating the region bounded by the x-axis, the curve y=3x^4, and the lines x=1 and x= -1. The axis of rotation is the y-axis. Homework Equations Washers method: V=∏∫ [(R)^2 - (r)^2]dr x = (y/3)^(1/4) The Attempt at a...

Homework Statement The thing that is lying on the disk(Disko), is rotating together with disko. After the rotary frequency of disko grew twice (N X 2), friction(rubbing) Force grew F=6 ( F + 6). You have to understand friction Force module at the original frequency. Homework Equations...

Homework Statement taken directly from Rindler A large disc rotates at uniform angular velocity ω in inertial frame S. Two observers O1 and O2 ride on the disc at radial distances r1 and r2. They carry clocks C1 and C2 they adjust to keep with clocks time with S, i.e., they have been adjusted...

1. A pot of 'm' water is rotating about Y axis with w angular velocity...Water is not compressible here... What's the height of the water? 2. Fc=m ω^2 r F=mg m/v=ρ=> 3. I solved the ques for rotation around X axis... Fc =mg From that I found out the h But then I found...

Hi so I am trying to build a rotating platform for a system consisting of two 12in. subs approximately 60 pounds, I would like it to rotate 180 degrees and then back with the flip of a switch if possible. I have absolutely no experience in this what-so-ever and all of the auto places want to...

[SIZE="4"]The next situation is presented 2 big circles (blue ones) are rotating in different directions. The left one is rotating clockwise and the right one rotates counter clockwise. Inside the 2 big circles, 2 small circles (pink ones) are embedded...

Hi, I have a standard cell which I would like to rotate. I would like to rotate it in such a way such that when I define some plane in the unrotated cell [hkl] that this same plane corresponds to the [001] plane in the rotated cell. I essentially want to keep the same unit cell, just rotate the...

Hello, I am first year mechanical engineering student and I am struggling with the concept of moment, rotation and angular velocities, accelerations of rigid bodies. Can someone recommend an article with problems or an excerpt from a book or something similar to help me. It would be great if...

Hi, This question is about a discussion in the two chief world systems, the second day about p 230 in the modern science library edition (around figures 10 and 11). I haven't found the excerpt online so I hope someone has the book. As an objection to a rotating earth, the claim that any...

In Minkowski spactime (Flat), if the coordinate system makes a rotation e.g. around y-axis (centred) , for the metric ds^2, how to make the tertad (flat spacetime) as the coordinate system rotats?

Dear All, Hi I am a teacher and also new to the forum! Can someone guide me what happens if Earth stops rotating suddenly! Thanks. Jayesh.

I've been considering petroleum engineering because of the rotating shift structure of drilling engineer work: such engineers typically work for 1-3 weeks, 12 hours a day, and then are off for an equal amount of time. However, lately I've become concerned about the job security of petroleum...

Hi, Homework Statement A horizontal smooth disk of radius R rotates around its axis with constant speed ω. At t=0 a mass m is thrown at speed v0 (in the lab's frame of reference) towards the center of the disk. I am asked to write down the velocity vector of the mass in the lab's frame of...

Homework Statement Consider a bucket quarter filled with oil. When the bucket is rotating with the angular velocity ω, derive the equation of the surface h(x), where h is measured from the lowest of the surface and x is measured from the rotational axis. Does it change if we replace oil by...

http://dev.physicslab.org/Document.aspx?doctype=3&filename=RotaryMotion_RotationalDynamicsPivotingRods.xmlin this example, the rod is swinging with one end pivoted. conservation of energy was used in this example. the change in potential energy was converted to kinetic energy, and mechanical...

Homework Statement Homework Equations Frotating = Finertial + Fcor + Fcf The Attempt at a Solution For the inertial field: F = -qv x b -kQq/r2 For the rotating field it would be the same term plus the coriolis and centrifugal forces. The issue I'm having trouble with is this: The v...

Homework Statement A cone of height h and base radius R is free to rotate about a fixed vertical axis. It has a thin groove cut in the surface. The cone is set rotating freely with angular speed ω0 and a small block of mass m is released in the top of the frictionless groove and allowed to...

Homework Statement A massless hoop is suspended horizontally and is free to rotate about a vertical axis through its center with a constant angular velocity (omega). Attached to the edge of the hoop is a simple pendulum that is restricted to oscillate in only the radial direction. find the...

My question is kinda simple but it has been causing me some trouble for a while. In the problem of the pendulum rotating about an axis, why isn't the angle of rotation about the axis a generalized coordinate? The doubt appears when i try to write the hamiltonian for the system and i don't know...

KErotational = (1/2)Iω2 420 = (1/2)Iω2 420 = (1/2)I(402) 420/(402) = (1/2)I 0.2625 = (1/2)I 2(0.2625) = I 0.525 = I 0.53 = I

Homework Statement In the attached image, find angular velocity of the rod and the velocities at points B and C. Homework Equations vB|A=0.3ω The Attempt at a Solution How do I know what angle the absolute velocity makes with the other vectors when put in a triangle? How would the velocity...

Homework Statement panofsky 10.3 Find the torque on a solid conducting cylinder rotating slowly in a uniform magnetic field perpendicular to the axis of the cylinder. The Attempt at a Solution let the radius of cylinder r, and the conductivity is σ, the rotating angular...

Einstein, for his GR theory he made a last important effort to make it valid also for rotating objects. So consider the following thought experiment. There is an observer A standing at the North Pole and another observer B sitting on a platform, turning clockwise once every 24 hours, both with...

Homework Statement A rod of length l swivels around an axis, denoted O in the drawing, located on the floor. The initial position is β=45°. A ball B is left to fall at the same time the rod is left to rotate. Who will arrive, first, to the floor: the ball or the edge A of the rod...

First off, sorry if this is a simple question, I'm very bad at electromagnetism. Homework Statement A metal ring of radius R rotates with constant angular velocity ω about a diameter. Perpendicular to the rotation axis is a constant magnetic induction field \underline{B}. Find the EMF...

hi, i have a motor conected to mcu via h bridge but it stops rotating after few minutes.may i know the reason for this. thanks

Homework Statement A uniform non-conducting ring of radius 0.816 cm and total charge 6.76 µC rotates with a constant angular speed of 1.73 rad/s around an axis perpendicular to the plane of the ring that passes through its center. What is the magnitude of the magnetic moment of the...

Hello, I am a high school student trying to learn physics out of Kleppner and Kolenkow. Unfortunately, the solutions to some of the problems are not available online, nor is a solutions manual available, so I am unable to find out where I am wrong in some cases, such as this one. I would...

Suppose we have a rod standing vertically and then slightly disturbed so it begins to fall. After it falls through some height or angle assuming a clockwise rotational fall I can see that the left end is sliding on the surface ( for simplicity I'm ignoring friction ) horizontally. Here I assume...

Homework Statement Oil and water are put in a cylindrical container. They can rotate at various frequency around the rotational symmetry axis. Consider gravitational and radial forces to find the form of the surface between the fluids. no friction, no mixing the surface has the form of a...

Homework Statement We have a bead sliding on a frictionless hoop oriented vertically. First the hoop rotates about its center with rotation axis perpendicular to its plane. Second, the hoop rotates about a vertical axis as well. In both of these cases, are the constraints holonomic or...

Homework Statement Three stars, each with the mass of our sun (1.9891E31 kg), form an equilateral triangle with sides long. The triangle has to rotate, because otherwise the stars would crash together in the center. What is the period of rotation? Homework Equations F1=GM2/r2 ƩF=0...

Hey guys, I know it late its a little past one here. But I'm doing an assignment due tomorrow at I've been stuck on the last question for at least an hour. Find the volume of the solid obtained by rotating the region bounded the curves Y=absolute value of x. and y = square root of (...

Homework Statement In a cylindrical container (with radius R) there are 2 fluids (separated like water and oil, fluid 1 lies under fluid 2) with given volumes V_i, given densities ρ_i. You let them rotate with respective angular frequencies ω_i. There is no friction. Find the functions of...

Thank you in advance for your help! The title pretty much says it all. I'm looking to write a 2D physics sim in which various objects can bounce off solid surfaces (without gravity). The objects are rotating and translating at a constant rate. We are dealing only with x and y - not z...

This isn't actually a homework question, I'm programming something, it's just what should be fairly simple math I'm just not certain how to do it. Assume I have a normalized vector which points directly up {0,1,0}. I also have another vector X. I'd like to rotate vector X along the...

OK, so I'm trying to build a hyper-fast rotating disk, probably of aluminum. The tensile strength is about 200MPa (note that this is a pressure, which makes sense), and I'm trying to calculate the tensile pressure throughout the disk. The point being to find out how fast I can spin the thing...

Homework Statement A massive cylindrical container of inner radius ##R## is rotating freely with an initial angular velocity ##w_0##. A liquid of density ρ is slowly injected into the container, until the container is fully filled except the center of the container. The angular velocity of the...