Axis Definition and 895 Threads

Hi all, I have run into a problem requiring the use of the parallel axis theorem. I'm kind of lost as to where to start. Can anyone help? A thin, uniform rod is bent into a square of side length a. If the total mass is M, find the moment of inertia about an axis through the center and...

Hey everyone, I need some help here. The question is to show that the wobble rate of a plate when thrown slightly off axis, is twice that of the spin rate. I don't even know how to start this problem. All I really know is that the inertia matrix can be written simply about body fixed axes. Thus...

A puck of mass 80.0 g and radius 4.20 cm slides along an air table at a speed of 1.50 m/s. It makes a glancing collision with a second puck of radius 6.00 cm and mass 140.0 g (initially at rest) such that their rims just touch. Because their rims are coated with instant-acting glue, the pucks...

hi I am having trouble with finding the neutral axis and second moment of a T-beam. here are the measurements of the beam: http://img354.imageshack.us/img354/8648/beam6xl.jpg i understand to find the neutral axis you divide the beam into 2 rectangles but iam having problem finding the...

in beam theory it is mentioned that there should be a neutral axis which remains constant in length before and after bending. Why should there be a neutral axis like this?

I was hoping you could give me a hint on how to find the equations of the axis of the ellipse of equation 5x^2-6xy+5y^2-4x-4y-4=0. I think this is supposed to be an exercise about lagrange multipliers or something related to the gradient, but i really don't know. I am clueless, i don't know any...

Inertia - Parallel Axis Theorem Two spheres with masses M and m are connected by a rigid rod of length L and negligible mass as in Figure 10.22 (M is on the left end and m is on the right end). For an axis perpendicular to the rod, show that the system has the minimum moment of intertia when...

If you have two standard 3d, orthogonal matrices representing axes of 3d coordinate systems of the same handedness, is it possible to find the vector about which you would rotate one of the matrices to get the other? If so, this would be a lot more intuitive than quaternions (at least for me)...

I have two questions. How do you find the equation of a cone given data points? I've found lots of info on the equation of a cone, but can't find anything on one that is rotated and not centered at the origin. What is the equation for a rotated translated cone? Second, given the equation of a...

Can anybody help me find the volume y=sinx, bounded by the y axis, and the line y=1. The axis of revolution is the line y=1. I tried so many times and I can't find the correct answer, in the sheet it says (pie^2)/2 - 2pie

Just a quick question about finding the magnetic induction field B on the axis of a circular coil shown on page 7 on http://www.physics.gla.ac.uk/~dland/ELMAG305/Elmag305txt5.pdf I understand why the field must be along the x-axis but why does (dlxr )x become dlrsin(alpha)? alpha doesn't seem...

Moment of inertia for a rod along the x-axis centered at the origin is : \int_{-L/2}^{L/2} r^2 \frac{M}{L} dr M/L denotes mass density, this evaluates to \frac{1}{12}mR^2 as we'd expect, but my questoin is, if the rod was not rotating about an axis through its center, but an axis at...

I would like to further understand rotational inertia. I understand that for a point mass, I = MR^2 and for a continuous object it is basically the sum of all "little" MR^2 for each element of that object. I get a little fuzzy when actually solving for I for an object. For example, if we have a...

how do we say that in a beam bending problem the bean cross section bends(rotates)around the centroidal axis. Why not about any other axis?

A CD has a mass of 17 g and a radius of 6.0 cm. When inserted into a player, the CD starts from rest and accelerates to an angular velocity of 20 rad/s in 0.65 s. Assuming the CD is a uniform solid disk, determine the net torque acting on it. I thought to use: torque = I * alpha...

Could someone please help me with a particular question to this problem? Consider a cube of mass m with edges of length a. The moment of inertia I_0 of the cube about an axis through its center of mass and perpendicular to one of its faces is given by I_0 = 1/6ma^2. Find I_edge, the moment...

http://arxiv.org/abs/astro-ph/0502237 The axis of evil Kate Land and Jo˜ao Magueijo Theoretical Physics Group, Imperial College, Prince Consort Road, London SW7 2BZ, UK (Dated: Feb 11, 2005) We examine previous claims for a preferred axis at (b, l)  (60,-100) in the cosmic radiation...

the center is (-3,4) and tangent to the y-axis how will I find the equation of the circle? I know what tangent means but at what point? Can someone give me a clue? :rolleyes:

How would you do this question determine the equation of the locus Locus whose points are equidistant from the x and y axis? :cry: I HATE LOCUS!

I'm doing an Exam correction an I can't see how this answer is found. Question: x^2 - \frac{\ y^2}{9} = 1 Find the length of the transverse axis. I took x^2 - \frac{\ y^2}{9} = 1 And plugged it into \frac{\ (x-h)^2}{b^2} - \frac{\ (y-k)^2}{a^2} = 1 to get \frac{\ (x-0)^2}{1^2}...

Determine the restrictions on the constants A, C and E such that the following equation is a parabola with a vertical axis of symmetry. Ax^2+Cy^2+x+Ey=0 a) A=0, C cannot=0, E cannot=0 b) A=0, C cannot=0, E=0 c) A cannot=0, C=0, E=0 d) A cannot=0, C=0, E cannot=0 i know that A cannot=0...

Can a wave rotate about its axis?? Can a transverse wave "rotate" about its longitudial axis (kind of like an airplane's "roll" maneuver)? If it could, i don't think we could detect it; if it did, i don't think anything will really get affected. But could it?? Not that it would...i mean...

i was wondering what causes the Earth's tilt on its axis. i was thinking that it might be from einsteins theory of gravity, in which a large object, such as the sun, causes a bend in space time forming gravity and causing Earth to rotate around it. any info would be great, thanks

A solid sphere of diameter 0.15m and mass 0.5kg is released and rolls without slipping down the ramp. The ramp is 0.81m high and is on a table. The table has a height of 1.40 meters. The balls move freely once it leaves the table. a) What is the moment of inertia of the ball about the axis of...

Hi guys we got a lab today and I have to answer a few questions... I want to make sure my answers are correct... Convex Lenses 1. How do we locate the principal axis? We locate the principal axis by directing a beam to the middle of the lens (what is this called? optical center?)...

hi this is my first post,and I hope i get the help I need;) equation of curve 2y^2=x^3 find the volume of the solid formed by the complete rotation about the y-axis of the region bounded by the curve the y azis and the line with the equation y=2 which lies in the first quadrant,*done this*...

4. [PSE6 10.P.014.] Figure P10.14 shows the drive train of a bicycle that has wheels 67.3 cm in diameter and pedal cranks 17.5 cm long. The cyclist pedals at a steady angular rate of 73.5 rev/min. The chain engages with a front sprocket 15.2 cm in diameter and a rear sprocket 7.45 cm in...

I am having a very hard time with this problem! Even my teacher had trouble with it(of course we are still expected to have it done on our homework!) 2 doors are uniform and identical. Door A rotates about an axis to its left edge and door B rotates about an axis through the center. The...

Help! tangent axis Use the parallel-axis theorem to find the moment of inertia of a solid sphere of mass M=3.80kg and radius R=2.30m about an axis that is tangent to the sphere. I am being thrown off this problem because the axis is TANGENT to the sphere and not through the center. According...

Hello again. I thought I had this problem figured out but once again, I did not. Here's the problem: A solid circular disk has a mass of 1.2kg and a radius of 0.12m. Each of three identical thin rods has a mass of 0.12kg. The rods are attached perpendicularly to the plane of the disk at...

I have some doubts on the following: When a wheel rolls without slipping, the point of contact of the wheel with the ground is instantaneously at rest. It is sometimes useful to think of the motion of the wheel as pure rotation about this "instantaneous axis". Points [on the wheel] close to...

"Real line" is used to mean real axis ["Real line" is used to mean real axis, i.e., a line with a fixed scale so that every real number corresponds to a unique point on the line. (http://mathworld.wolfram.com/RealLine.html) There are two basic states that stand in the basis of the real-line...

Well, I'm not even sure if freefall is the right word, but my first quandary is as followed: If two objects fall from the same height, and one object will begin to rotate after it has been release (ie. a yoyo), while the other will not rotate, then the rotating object will accelerate slower...

how does the Earth keep spining on its axis? is it because it still has the energy it gained when it was formed because it doesn't lose energy into space cause there's no particles out there, but then i was thinking does it loes any energy through IR radiation? just curious.

Problem 1. Consider the equation y=a(x-r_1)(x+r_2) Write the equation of the axis of symmetry.

i've been stuck on this problem for an hour now. how do you find the surface area for y=(x)^1/2 when 0_<x_<2, rotating about the x axis?

How does axis of rotation of a gyroscope alter from the geodetic and framedragging effects... and why is the axis pointing in a constant direction in the first place?

Hi! Can someone prove, that magnetic field can be axialy rotated. I proved it can not. look at http://www.geocities.com/terella1/ It looks there is something in basic physics that most scientists missed or were even unaware. Tha long known Faraday Paradox of rotating magnetic field. My...

The quadrant of the ellipse \frac{x^2}{a^2}+\frac{y^2}{b^2} = 1. lying in the first quadrant, revolves about the line joining the extremities of the major and minor axis. Show that the volume of the solid generated is \frac{\pi a^2 b^2}{\sqrt{a^2+b^2}} (\frac{5}{3} - \frac{\pi}{2}). I tried...

The problem is this: a rigid object is in free-fall, and a force is applied so that it would be a torque if the object had a fixed axis through its center of mass. But the object doesn't have such an axis. How much of that force turns into linear motion, and how much of it goes into rotation...

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...

if anyone can please help me with these at least tell me how to start them that would be great... CJ5 4.P.013.] Only two forces act on an object (mass = 3.10 kg), as in the drawing. (F = 50.0 N.)the other force is 40N Find the magnitude and direction (relative to the x axis) of the...

An ellipse on the xy-plane has foci at (-41, 23) and (115, 42). The ellipse is tangent to the x-axis. What is the length of the major axis of the ellipse?

This is algebra. I think I missed this part in class. I know a Hyperbola has a conjugate axis, but is this the hyperbolas equivlent of an elipise's minor axis? If so, how do you find the measurement? I'm writing a forumla for a hyprbola in standard form and need to find b^2. Thanks.

how does the rotation of the Earth around the axis bring about changes in the climate resulting in the 4 seasons? and why do the countries at the equator not experience seasonel changes?