Homework Statement
Finding the area of a disc by integration of rings.
Homework Equations
A ring of radius r and thickness dr has an area of 2 \pi rdr.
The Attempt at a Solution
Why isn't it \pi (2rdr + (dr)^2)?
[SOLVED] Convexity of Open Disc
I'm trying to prove that the open disc in the complex plane given by D = {z : |z - w| < r} is convex.
Let p and q be two points in D. The line segment from p to q is L = {(1 - t)p + tq : 0 <= t <= 1}. Let u be a point an arbitrary point on this segment. If I...
A pendulum hanging from the edge of a horizontal disk rotating around an axis at a constant rate. The angle that the rotating pendulum makes with the vertical increases with the speed of rotation and can be used as an indicator of speed, calculate speed of disck if R = 0.2m, l = 0.3m and the...
Greetings all!
There is a bit of a debate in the world of mountain bikes, concerning the conventional 26" wheel diameter versus the rising popularity of the 29" wheel size (nominal diameters).
One of the popular beliefs is that the 29" wheel requires a larger brake rotor than a 26" wheel...
Hi, i need calculate the stress energy tensor for rotating 3D-disc in arbitrary rotation.
where i can find some hint or perfomed calculations?
thank you
Suppose you have a very strong, spinning disc with a diameter of say 10 km in length. At the centre the centripetal velocity is approaching the speed of light, how would we observe the outer edge of the disc to be.
Homework Statement
The inner and outer radii of a compact disc are 25 mm and 58 mm. As the disc spins inside a CD player, the track is scanned at a constant linear speed of 1.25m/s. The maximum playing time of a CD is 74.0 min. What is the average angular acceleration of a maximum-duration...
How might one detect the plane of an accretion disc of a Black Hole? Might it just be assumed, by the orbital plane of a BH binary system? http://en.wikipedia.org/wiki/Accretion_disc"
[SOLVED] Moment of Inertia Problem
Homework Statement
A compound disk of outside diameter 140.0cm is made up of a uniform solid disk of radius 50.0cm and area density of 3.00 g/cm^2 surrounded by a concentric ring of inner radius 50.0cm, outer radius 70.0cm, and area density 2.00 g/cm^2. Find...
I am driving a drum head with a rod. The rod goes up and down as the radius of a disc changes length (please see attached PDF). There is a gradual raise of the drum head, and then an abrupt drop. But there is a kink that the rod needs to overcome.
Any suggestions on how to achieve this...
1.
If two coins are placed on a rotating disc (constant speed), what forces act on the coins, at what direction and in what proportions?
(The coins aren't sliding)
Gravity is one, and the normal force is the one counteracting on that.
But what forces could be expected in a horizontal...
Homework Statement
Find the angular velocity and period of oscillation of a solid disc of mass m and radius R about a point on it’s surface.
Homework Equations
?
The Attempt at a Solution
This is really giving me trouble because it seems like a SHO problem mixed with a rotational motion...
Homework Statement
Find the potential outside a thin, circular disc with charge q.
Homework Equations
Laplace's equation
DivgradU=0
The Attempt at a Solution
Since the problem implies symmetry around phi its obvious the solution doesn't depend on phi.
I separate the...
Homework Statement
Compact Disc. A compact disc (CD) stores music in a coded pattern of tiny pits 10^-7 m deep. The pits are arranged in a track that spirals outward toward the rim of the disc; the inner and outer radii of this spiral are 25.0 mm and 58.0 mm, respectively. As the disc spins...
I have begun modelling a basic braking system in Simulink/Matlab for my final year project. The model is designed from the time force is exerted to the pedal at a particular velocity, to when heat is produced from the frictional force between the brake pad and disc.
I have the modelling...
Hi
Does anyone know how changing the diameter of the conducting disc used in Faraday's disc (a homopolar generator) would affect the current and voltage induced in the disc.
e.g. would a disc with a greater diameter produce a greater current and voltage than that of a disc with a smaller...
Homework Statement
A digital audio compact disc carries data, with each bit occupying 0.6 (mu)m, along a continuous spiral track from the inner circumference of the disc to the outside edge. A CD player turns the disc to carry the track counterclockwise above a lens at a constant speed of 1.3...
Has anyone here heard about the new data storage medium that is being researched? Apparently it'll be able to store up to 3.9 terrabytes of data, which is insane.
Anyway, I checked out this article on Wikipedia to see how it worked...
http://en.wikipedia.org/wiki/Holographic_Discs...
One more problem on a tough worksheet...I have tried it for a while, but can't find an equation(s) suitable for the problem...
A constant force of 12N is applied to the axle of a disc rolling along a flat plane. The disc has mass m=22kg, diameter D=.50m, and rotational inertia I=.688kgm^2...
Rotating Disc & Speed of Light ?!
If a point on a disc's outer edge is traveling close to the speed of light and things contract in the direction of the acceleration at those speeds (relative to a stationary observer) would that mean the disc's radius stays the same but the circumfrance...
Oh since this got moved: It's not for any course or class so I'm not following any book.
I'm not sure if anyone will be able to answer this but I'll ask anyway:
I've solved laplaces equation in cyclindrical coordinates for a disc of radius 'a' and constant potential V on the disk (disc in z=0...
Hey guys, so I'm back in school after an 8-month break, and I'm feeling a bit rusty :rolleyes:
So I've got a flat disc of radius A, with constant density p, in the z=0 plane. I want to calculate the gravitational field at any point up or down the z-axis.
I integrated the potential over the...
I'm doing a project on accretion disks, and I was wondering if anyone could suggest something interesting relating to their observation that I could talk about. One thing I remember reading was that accretion discs are one of the most compelling means of proving the existence of black holes...
Hello All!
I have one machine. The disc (Horizontal place) is rotating and connecting to the shaft which is connecting to gear box and ac motor.
I would like to k now the torque of rotating disc for some interval such as 10s, 20s, 30s, to take reading , but I do not have money to buy...
A disc of moment of inertia 29.1 kg m2 is made to rotate about an axis through its centre by a torque of T . The disc starts from rest and, after {t} s, has kinetic energy {k} J.
The torque is removed when the disc is rotating at 8.0 rad s-1 . An opposing torque of 13.2 N m is applied to slow...
moment on a circular disc(moment applied in the centre)
A circular disc is hinged in the centre. I am applying a moment at the centre. The result is that the disc will rotate with an angular acceleration "a"
moment on a circular disc(moment applied not in the centre)
A circular...
Electric field of Charged disc
Find the electric field at a distance 'z' above a uniformly charged disk of radius R.
I have solved this problem. Can someone just clarify if my solution is right?
I couldn't attach a diagram..sorry!
Solution: Using conventional notations,
\sigma is the...
i have a rotating disc. I have a tachometer and a sensor tape. Where should
i stick the tape to measure the rpm correctly? How tachometer works?
One more question.
a rotating disc has kinetic energy. Why we study energy of a rotating.
Now if i stop the rotating disc according to law of...
A thin string has been wound around a homogenous circular disc A in such a way that the disc can oroll on a horiz0ontal surface. The mass of the disc is M and its radius is R. The string goes around a small frictionless pulley C at a height 2Rabove the horizontal table B. To the free end of teh...
A few minutes ago, I had a CD in my computer which I was listening to. I switched the CD for another one, and it didn't recognize that CD. I tried 4 other CD's, and my computer keeps showing a little icon oc a CD next to my mouse right when the CD is put in, but then acts as if there's no CD in...
I'm stuck on a miniquestion in my HW that is hindering the entire problem, so here it is.
A disc of mass M, radius R, Icm =1/2MR^2 is rolling down an incline dragging a mass M attached with a light rod to a bearing at the center of the disc. The friction coefficients are the same for both...
What do the strange values on disc capacitors signify exa 005 and
5D 1KV , why can't they just be abbreviated in a more intuative way like for exa just 10 micro farads ?
Also for a small mic how can I tell apart which ends which + or 1 and what do the letters HAI signify on some...
Two frictionless discs on air table, initially at rest, are driven apart by an explosion with velocities of 9.0m/s and 5.0m/s what is ratio of masses?
how do i get masses if i don't know Momentum ? +__+
Problem: The coefficient of kinetic friction between the 100 lb disk and the surface of the conveyor belt is 0.2. If the conveyor belt is moving with a speed of 6 ft/s when the disk is placed in contact with it determine the number of revolutions the disk makes before it reaches a constant...
I want to put some permanent ink on disc golf discs, i don't know if any of you are familiar with these frisbee type discs...
I was wondering what the best kinds of ink to use are and how to apply the ink to the disc so that it does not run. i have no experience in this type of work so it's...
If I have a solid disc with a diameter of 30 cm and a mass of 700 grams with a speed of 45 rpm, and a mass of 350 grams falls 6 cm from center what is the speed of the disc. There are also no external torques.
I have no problem solving the angular momentum of the disc before the mass falls...
What if we had a large and massive object shaped like a disc (look at the attachment) and we would walk on its edge. If we would step on the flat part what would happen?
P.S. I am going on holidays for a fe days so i won't be abel to check out your answers very soon.
I think I'm starting to abuse this forum. Anyways, it seems that I haven't grasped the concept of angular acceleration yet since I'm having trouble solving this problem:
Suppose I have a disc laying on the x-y plane with center at the origin. Suppose the disc is rotating about the z-axis with...
A question,
I have a plastic disc with a coil wound around is axis of rotation. The coil carries current I. Now the disc carries charges at its circumference. Now the current flowing in the coil is brought to 0 instantaneously. This creates Electric Field to be produced that travel in...
Famous Hoover "disc" quote debunked: Ivan Seeking
On television and in most of the current Roswell literature, this quote is often cited as evidence that Hoover had a continuing interest in the Roswell disc and the "other discs recovered". Here, thanks to some skeptical prodding by Zoobyshoe...
My friend just bought a mini disc player, and apparently it uses an optical cable to connect to a computer. I think I know what an optical cable is, but I've never heard of an optical port, and I've never seen one on a comp before. Are they a fairly recent development, or am I just blind?