Rotating Definition and 1000 Threads

I'm asking myself how can I achieve the next solution: I've a plastic case with the shape like a box, where I've 2 blades: one in the front and the second in the other. My question is how can I rotate the disks in the different direction: one clockwise and the other counter-clockwise. What...

Why the speed of the coin rotating in a table increases when it begins to stop ?

Hey everyone, As part of my PhD project I'm trying to design a small bioreactor in which I will be growing animal cells. This bioreactor will basically consist of a hollow cylindrical vessel that has an impeller in it which will keep the liquid medium in the vessel well mixed. The impeller I am...

I may be on the wrong page but I had a question. You see, I do not have your math skills so I am stuck with an idea, and I have no way of finding out if I am on the right track. Question: "Can a gyroscopic rotating magnetic field render inertia mute?"

The problem statement: What I have managed to do: This problem seems a bit tricky at first because it is talking about rotating a crystal while also changing the voltage - changing two variables at the same time makes no sense to me. This is why I assumed that while we change the voltage...

It's a pretty straight-forward question, and it got me confused since most articles on the internet mention planes of simultaneity in the context of inertial frames. So if rotating frames also have planes of simultaneity, what SR says about it and how does it differ from the planes of...

there is a gyro... put it on an electronic scales which has a smooth surface...it shows the weight is M. then, let it rotate... keep increasing the angular velocity... will the weight display increase? or else?

I read that if a bar is pivoted at one end and is rotating in a horizontal plane, the tension at a specific point decreases as you go away from the pivoted end. Only inference I could draw from this is that the centrifugal force, which is the cause of tension, increses as you go towards the...

I have a conceptual issue with wheel friction that has been bothering me for a while. Consider the wheels on a car set to cruise control such that they rotate with constant angular velocity. Neither the wheel nor the ground are deformable (so we can ignore rolling friction) and the wheels slip...

Hi all, new on here so thanks in advance for your responce's I am an avid cyclist and competant engineer, i dislike oil and gas so much i do not own a car. I cycle everywhere. I am tired of wanting to go long distances without assistance or a high top speed. I want to build a cycle with...

Homework Statement In Cartesian coordinaate system, we describe the rotation of a cylinder. The axis of the cylinder has the same direction as the basis vector e3. Angular velocity is described by vector w = 2e1 - 5e2 + 7e3 rad/s. I must find the velocity vector (v) of a point P that is...

To understand centripetal force due to friction better, I came up with this problem. I'm not entirely sure of my solution, though, so I'd be glad if someone else took it up too and suggested a way to work it out: Two identical blocks, each of mass m, connected by a spring of spring constant k...

A common solution to the problem of artificial gravity in space is to have the spaceship or station rotate, and the centrifugal force would "pull" objects toward the outside. What I haven't seen considered is that the station would have to have some kind of central motor attached to a central...

I want to solve a following problem. Imagine a collection of massive points. Each point has mass, position, velocity, moment of inertia, orientation and spin. We can calculate its total center of mass, total momentum and total angular momentum. The task is to transform the coordinate system...

Homework Statement Four rockets attached to a (wheel) space station exert a force of 65.5N to rotate it . The space station's angular velocity is increased at a constant acceleration of 3.63 x 10-3 rads-2. Each rocket is 11.2m away from the centre. Calculate the rotational inertia of the...

Homework Statement r=0.10 m B=0.65 T Homework Equations ampere's law? The Attempt at a Solution

I want to transform from rectangular coordinates ( xyz) to (x",y",z") rectangular coordinates that is rotated at the origin as show in the attachment. Then I want to transform (x",y",z") rectangular coordinates into Spherical coordinates. Attach is the method I use, I want to verify I am doing...

How can we tell whether the universe is rotating or not? Have we made a definitive determination yet? How does the notion of a rotating universe even have any meaning? What would a rotating universe be rotating in reference to? And lastly, if the universe were somehow rotating, would it...

A magnetic field of B=0.5B0z^ is present when a loop with radius r is rotated around the y-axis with angular velocity of w=9 rad/s. What is the induced emf? Well: flux = SB*dA = SBdAcosq(t) = Bcosq(t)SdA = 0.5B0*pi*r^2cosq(t) d(flux)/dt = 0.5B0*pi*r^2*-sinq(t)*dq(t)/dt =...

1.Determine the volume of the solid obtained by rotating the area between the x-axis and the graph of the function given by f(x) = cos(x^2) with x between (pi/2)^0.5 and (3pi/2)^0.5 ,about the y-axis. 2.What is the volume if the above area is rotated about the line given by x=4. Thank you in...

Homework Statement A metal disk is rotating with constant angular velocity in a constant magnetic field perpendicular to it. Use Faraday's law to fint the the induced voltage difference between the two points on the wire. The attempt at a solution So to use Faraday's Law, I need to...

A rotating mirror with 16 sides was used to measure the tine it took light to travel 3.5km to a concave mirror and back. At what frequency did the rotating mirror need to turn to make 1/16th of a rotation in the time it took light to travel to 3.5km and back again? im having a bit of...

If any of you have the Third Edition of Classical Electrodynamics by John David Jackson, turn to section 11.8, as that's where I'm getting all this from. If not, you should still be able to follow along. In said section, Jackson gives us this equation that relates any physical vector G in a...

An electron as shown by the Stern Gerlach experiment behaves like a dipole (albeit only in one of two states). I have been trying to figure out how this is so and drew up the following sketches. A few assumptions were made about electrons such as 'distribution' of charge assuming static...

Homework Statement A long hollow nonconducting cylinder (radius R= 0.060 m, length L= 0.70 m) carries a uniform charge per unit area of σ= 4.0 C/m^2 on its surface. Beginning from rest, an externally applied torque causes the cylinder to rotate at constant acceleration α= 40 rad/s^2 about the...

Hi. I need to find the mass (relativistic mass?) Of an object in rotation. Say I have a string with a small rock tied to the end. The relevant variables are: A) The circumference of the weights path. B) The weight of the rock itself. C) The revolutions per minute that B...

I need to calculate the angular velocity of a 2kg mass rotating in a horizontal circle of 2m radius where 1 revolution takes 4 seconds ω=v/r My attempt was this : 4/360=.0111111×57.3=.636rs.

Coriolis effect - In a non-friction system, f I roll something along the surface of the planet from on of the poles to the equator, it will appear to move to the west, it will essentially stay behind the planets rotation and actually rotate it in the opposite direction. Now, if we add friction...

Figure Q4. illustrates a rotor assembly with out-of-balance rotor discs in planes A, B and C. The out-of-balance mass x radius products in planes A and C are as indicated in the figure. The out-of-balance mBrB in plane B and its angular position \ThetaB are such that the system is in static...

If we look at the classical formula for the conservation of angular momentum, L=mvr, we can easily see that, if the radius of a rotating body is shortened, its velocity must increase in order to conserve L, and vice-versa. Again, the classical conception we have of this formula is its...

Homework Statement A ball of mass m is attached via a rod of length x to an axle that rotates with angular velocity ω. You can consider the ball to be a point mass. m = 5 kg, x = 0.3 m, y = 0.4 m, ω= 30 rad/s (a) What is the linear momentum (direction and magnitude) of the ball? (b) What...

Homework Statement Show that, owing to the rotation of the Earth on its axis, the apparent weight of an object of mass m at latitude λ is : m((g-ω^{2}Rcos^{2}λ)^{2}-(ω^{2}Rcosλsinλ)^{2})^{1/2} where ω is the angular velocity of the Earth and R its radius. The first space travellers to reach...

Homework Statement A wheel, mounted on a vertical shaft of negligible rotational inertia, is rotating at 500 rpm (CCW from above). Part a) asks to find the new angular velocity if an identical wheel is dropped onto the shaft. I got this part right. Part b) is: Now suppose the dropped wheel...

Part v is where I'm stuck. All relevant equations and the bit where I'm stuck are in the second attachment with my workings

Homework Statement A thin and uniform bar has a length of 2.00 m and weighs 12.0 kg. It is rotating from one end on a pivot 5 times every three seconds. What is its kinetic energy? This is its hint: break the bar up into infinitesimal segments of mass dm and integrate to add up the...

Homework Statement Show for a solid spherical ball of mass m rotating about an axis through its center with a charge q uniformly distributed on the surface of the ball that the magnetic moment μ is related to the angular momentum L by the relation μ=(5q/6mc)L Homework Equations μ=IA/c...

Homework Statement Homework Equations \frac{\partial\mathcal{L} }{\partial q} = \frac{d}{dt} \frac{\partial \mathcal{L}}{\partial \dot{q}} \cos (\alpha - \beta) = cos(\alpha)cos(\beta) + sin(\alpha)sin(\beta) The Attempt at a Solution The position of the center is...

The angular momentum of the electromagnetic field is defined as, $$ \vec{L_{em}} = \int \vec{l_{em}} d^3r. $$ To solve this for a rotating sphere I must consider the cases where r < R and r > R. When I did this problem I thought that there would be two solutions, one for both cases; however...

Homework Statement Not a homework problem but: I am revising rotating frames of reference right now and I know that: a_{inertial}=(\frac{dv}{dt}_{inertial})_{rot}+(w x v_{inertial}) But I cannot seem to understand what (\frac{dv}{dt}_{inertial})_{rot} means; more so the 'rotational' bit...

Homework Statement Imagine that a circular disc is rotating with a frictionless ball on it( ball is not at center of the disc) If we observe the motion of the ball from the rotating frame of reference, then how can we describe its motion? Homework Equations The Attempt at a...

Why does an object on a rotating disc fly off the disc as the speed of rotation is increased? To accelerate, the object must experience a net force in the direction of acceleration -- in this case, away from the disc, perpendicular to the object's velocity vector. But what is this force...

I got stuck going over the derivation of fictitious forces in rotating frames. see specifically http://en.wikipedia.org/wiki/Rotating_reference_frame#Time_derivatives_in_the_two_frames this page to see the proof I'm talking about (sorry i'd love to be able to explain it by myself but...

Hey guys, I am new to this forum, I have a problem and I can't get my head around it. so basically, I have a gate that rotates in water about a pier located in the middle (the gate is is 20 m length from the middle pier on both sides, so total length is 40 m). how do i calculate the force...

Homework Statement The body is formed of slender rod and rotates about a fixed axis through point O with the indicated angular properties. If ω = 4.6 rad/s and α = 4.4 rad/s2, determine the instantaneous velocity and acceleration of point A. I have attached an image of the question Homework...

Homework Statement Rotating with angular velocity ##ω_0## solid homogeneous cylinder of radius ##r## placed without starting forward speed at the bottom of the inclined plane, forming an angle ##\alpha## with the horizontal plane, and starts to roll in up. Determine the time during which the...

Will a ball placed tightly (radius of ball=width of groove) in a groove(length of grove along radius) on a rotating disk have any motion along the groove. The frictional force is zero.

A question I was doing asked to find the equation describing the surface of water placed in a cylinder rotating about its central axis. The question asserts that in the rotating frame, the water is at rest, and centrifugal force and the gravitational force of a volume element are perpendicular...

I assume that the equation that applies for this problem is M = mg * r. The large gear is rigid while the small gear rotates about the axis which passes through the center of the large gear by rotating a motor. What is the momentum which is required to turn the motor? I'm confused because...

Homework Statement A particle of mass m is free to slide on a thin rod. The rod rotates in a plane about one end at a constant angular velocity w. Show that the motion is given by r=Ae^(-γt)+Be^(γt), where γ is a constant which you must find and A and B are arbitrary constants. Neglect...

Homework Statement A disk rotates with angular velocity w. Two masses, Ma and Mb, slide without friction in a groove passing through the cnter of the disk. They are connected by a light string of length L, and are initially held in position by a catch, with mass Ma at distance Ra from the...