Axis Definition and 895 Threads

Homework Statement A wheel is comprised of two 50.0 cm long thin rods of negligible mass and a thin metal ring with a mass of 10.00 kg, mounted on a very low friction bearing. A 100 gram lead weight is shot horizontally at the stationary wheel with an initial speed of 50.0 m/s and sticks to...

Homework Statement 6x^2-6xy+14y^2-45=0 Two recording devices are set 2400 feet apart, with the device at Point A to the west of the device at point B. At a point on a line between the devices, 400 feet from point B, a small amount of explosive is detonated. The recording devices record...

Say I have an X-ray binary system of a B2 main-sequence star with an unseen companion (i.e., black hole). They have a separation of 20 million km and an orbital period of 4 days. How do I figure out what the semi-major axis is? I need it for the formula for Kepler's Version of Newton's Third...

Homework Statement A solid door of mass 37.80 kg is 2.30 m high, 1.70 m wide, and 2.53 cm thick. What is the moment of inertia of the door about the axis through its hinges? Homework Equations I= Icm + MD^2 Icm = 1/12[M (a^2 +b^2 )] formula for inertia of a rectangular plate. The...

Note this is physics I This should be the right section as this is not homework.. Ok I'm having trouble understanding the concepts of rolling without friction, kinetic energy linear and kinetic energy rotational. I have a hard time following my professor in class and usually like to go...

Hey guys, I am having some trouble understanding this problem. The horizontal x-axis is drawn through the centroid C of the area shown, and it divides the area into two component areas A1 and A2. Determine the first moment of each component area with respect to the x axis...

Homework Statement What is the moment of inertia of a solid cylinder (of mass 8.41kg and radius 7.5cm) rotating about an axis parallel to the symmetry axis but passing through the edge of the cylinder?Homework Equations I=.5mr2, but how does this change when the axis is passing through the edge...

Homework Statement A wheel of diameter 26.0 cm is constrained to rotate in the xy plane, about the z axis, which passes through its center. A force F = ( - 31.0 i + 49.0 j )N acts at a point on the edge of the wheel that lies exactly on the x-axis at a particular instant. What is the...

Homework Statement How do I find the angle between r and the X axis?Homework Equations The Attempt at a Solution My attempt is here: https://www.physicsforums.com/attachment.php?attachmentid=29307&d=1287751693 However the computer says 69.3 degrees is incorrect.

Hello! I'm very new to MATLAB and came across a problem: I need on the X axis values from 1 to 1024, only the powers of 2. I managed to get MATLAB to show only these values but as they would be when all the values are shown (1 and 2 are one ever the other and 512 and 1024 are far away one from...

Homework Statement Four identical particles of mass 0.475 kg each are placed at the vertices of a 1.73 m x 1.73 m square and held there by four massless rods, which form the sides of the square. What is the rotational inertia of this rigid body about an axis that (a) passes through the...

Homework Statement How do you find the angle between the resultant and the x-axis? Please refer to the link in the picture. I just don't know how to get theta which is 10.26 degrees. Homework Equations https://www.physicsforums.com/attachment.php?attachmentid=29314&d=1287763774 The...

Suppose we have a uniform disk and two forces are acting tangentially at the rim (both pointing in the same direction and parallel to each other and at diametrically opposite ends of the disk). Since the disk does not rotate the sum of torques about an axis passing thorugh the center of the...

Electric potential at point x on the axis of a ring of charge density "eta" Homework Statement A circular disk of radius R and total charge Q has the charge distributed with surface charge density \eta = cr, where c is a constant. Find an expression for the electric potential at distance z on...

I'm not sure if this is the right place for this question, but I didn't see a forum specifically about software. I'm trying to define a function in MathCAD that describes the rotation of a body vector about an axis u by an angle ɸ. What I've typed in is: R(ɸ,u):= [ 3x3 matrix where each...

I'm working on a complex analysis problem from Arfken. Integrate[ (cos(b*x)-cos(a*x))/(x^2), {x, -Infinity, Infinity}] and show that it is equal to Pi*(a-b) Attempt: I first look at a related problem (or one that I think is related). => f(x) = sin(x)/x => f(z) = sin(z)/z...

Hello Everyone, Below are three questions relating to the integration between curves that have been bugging me for some time now. I know how to integrate between curves. I know how to integrate between x and y, but when given equations like the ones below I am lost as to how to figure out 2...

A chiropractor performs a lumbar spinous pull manipulative procedure. Using instrumentation , she determines 3D coordinates of the axis of rotation of the contacted verebra at t = 15 msec relative to the local axis system as shown. A uniaxial load cell at the spinous process measures a force...

Homework Statement As per Griffiths 3.21, I am given the on axis potential a distance r from a uniformly charged disk of radius R as a function of \sigma. Using this and the general solution for laplace's equation in spherical coordinates with azimuthal symmetry, calculate the first three...

I need to write the letter p with a circumflex over it for an axis lable on a graph in matlab. Any ideas how I can do this?

Hey PhysicsForums. Long time reader looking for some assistance Homework Statement [PLAIN]http://img205.imageshack.us/img205/3923/physicsg.jpg 2. The attempt at a solution I'm pretty sure the idea is to find the unit position vector to point A, and the force vector F. I found...

Homework Statement What is the moment of inertia of the plate about z axis? Homework Equations The Attempt at a Solution Consider the isosceles triangle to be a part of a square of side l/root(2) Its mass will be 2M We know that its moment of inertia about the centre...

1. (a) A particle has ~r(0) = (4 m)j and ~v(0) = (2 m/s)i. If its acceleration is constant and given by ~a = −(2 m/s2) (i+j), at what time t does the particle first cross the x axis? Answer in units of s. (b) At what time t is the particle moving parallel to the y axis; that is, in the...

Homework Statement A ball P of mass m kg is dropped from a point A, which is 2 m vertically above a point B on a horizontal floor. After P hits the floor at B, it rebounds and hits another ball Q, of the same mass, which has also been dropped from A. The impact between the two balls is...

Hello. Can anyone tell me what is the "axis of figure" or "figure axis" ? This is in the context of rigid bodies, rotation, and moment of inertia.

Homework Statement 2\pi \int_0^6 y\sqrt{25- (y- 1)^2}dy + 5\pi That's the integral i need solved 2. The attempt at a solution[/b] so first i subbed u=y-1 took the 2 pi out of the integral that got me 2 integrals u*sqrt(25-(u)^2) du + sqrt(25-(u)^2) du the first integral =...

1. Homework Statement k so here is the equation i need help with that will find me the volume of a sphere 2*pi*y*sqrt(25-(y-1)^2) dy - 5*pi from 0 to 6 the 5 pi is the volume of a cylinder 2. Steps so first i subbed u=y-1 took the 2 pi out of the integral that got me 2 integrals...

Hi..I have a basic question regarding the equation of an ellipse. Let's say I ahve an ellipse with major and minor axes 2a and 2b respectively. Now, to check whether a point lies inside this ellipse, its fairly simple...I can just use the standars ellipse equation for that. Now, if my major axis...

1. Hi all, I'm doing a simulation on 3 different cantilever beam as shown in the attached figure. a) is the beam with only width varying from the base to the free end (height stay constant along the beam) , b) is the beam height varying from the base to the free end (width stay constant along...

hi, I am plotting a 1D graph in root (TH1F pointer). currently the y-axis gives the number of entries in each bin along my x-axis. how do i change it so that it is actually the number of entries in each bin divided by the total number of entries. thanks

Hi!, I'm well into the world of computer graphics. Love to say it was great but well, it isn't. I would like to know how I can take any object and have it orientate so its centre aligns perfectly with any arbitrary axis. Think of a cylinder at the origin pointing down the x-axis. Well I...

Hi, everyone. I was told that when a beam is short, L<=5H, the equation of "Stres=Moment*/2nd moment of initeria" is not valid (how). (where H = deapth of beam ; L is the location of F acting on that beam) Is that ture and is that relate to principle axis? Also if it is ture, why...

Hi all, As the sun is an oblate spheroid and is rotating, should not the axis of rotation be precessing, much like the Earth does? What is the axial tilt angle and what is the precession period in years? Also, what is the amplitude and period of the nutation? Are there are equations for...

Homework Statement This is the cross sectional are of the shape: http://img38.imageshack.us/i/shapep.jpg/" It's made of 2 10"x1" plates. (Picture is not to scale) Q (first moment of inertia) above and below the neutral axis should be the same. For some reasons, my calculated Q above is...

how to rotate the shaft and to move it linearly in a single axis

Does the ball rotate about its axis?! Hi Newbie here, I have a disagreement with an associate. I say that a ball on a string moving in a horizontal circular path rotates about an axis perpendicular to the said circle. He insists that it doesn't as it would wind up the string if it did...

I hope this the right place to post my question... should it be, "we can define a as half the sum of distances..."? please correct and explain if I'm mistaken thanks

Homework Statement Easy question: Find the centroid of x=2-(y^2) and the y axis Homework Equations The Attempt at a Solution Already calculated, I got an area of (4/3)(√2) Cx = 4/5 Cy = 0 When calculating Cx, in the book they have: Integral (x)(√(2-x)) And go...

The x-axis and y-axis are interchanged in the figure by running the following MATLAB function I wrote. Could anyone help me to get it corrected? Thanks in advance for any helpful answer. function axislabeling(n) x=1:1:n; y=1:1:n; z=zeros(n,n); for i=1:n for j=1:n z(i,j)=i; end end...

1. A tank is formed by revolving y = 3x^2, x = [0,2] around the y-axis is filled to the 4 feet point with water (w = 62.4 lb/ft^3). Find the work necessary to pump the water out of the tank over the top. I got the integral being from a = 0 and b = 4 and integrating [(12y-y^2)/3]dy with w and...

1. Find the area of the surface generated by revolving y = (sqrt)(2x-x^2), x = [0,1] a. About the x axis b. About the y-axis This problem is from the section about surface area revolving around an axis. I actually did the problem but I am not sure on my answer. For around the...

Homework Statement A uniform metre-rule is pivoted to rotate about a horizontal axisthrough the 40-cm mark. The stick has a mass/unit length of \mu kg/m and its rotational inertia about this pivot is 0.093 \mu kg/m2. It is released from rest in a horizontal position. What is the magnitude of...

suppose i have a solid rod of length 2L, connecting two identical point masses on either side, and this system is spining around the center of mass at a steady angular speed of \omega. another identical point mass is placed so that it collides with one of the point masses when the rod is...

Hi. I am using a 3 axis accelerometer for motion detection. I can easily determine the tilt using simple triginometry but cannot determine the movement in a particular direction. For example the sensor is at 45 degrees to the floor so the x,z coordinates are x = 0.5, z = 0.5. So if I keep the...

Saturn takes about 10 years to go around the Sun once. What is the semi-major axis of Saturn's orbit?

Homework Statement Derive an expression for the moment of inertia about the axis of symmetry for a cylinder of mass M , length L and radius a, where the mass density decreases as a function of distance from the axis as 1/r Homework Equations The Attempt at a Solution 1) am i...

If an object is rotating about the axis of symmetry and you are trying to find the angular momentum about the mass centre g. Does a rotation about the axis of symmetry correspond to a rotation about the principle axis? For this question i am trying to find the angular momentum about the mass...

hi everyone! I'm sorry if this seems like a really easy question, but... Suppose I have a device in which manually rotating gear A clockwise causes gear B to rotate clockwise. If gear A and gear B are at a weird angle to each other (say 35 degrees), what sort of intermediate parts could I use...

my question is... the semimajor axis of the orbit of Jupiter is 7.8*108. If an asteroid has an orbital period half of that of Jupiter what is the semi major axis? All i did was times 7.8*108 by 1/2 and got 3.9*108. Seems to simple!?? any comments much appreciated

my question is... the semimajor axis of the orbit of Jupiter is 7.8*108. If an asteroid has an orbital period half of that of Jupiter what is the semi major axis? All i did was times 7.8*108 by 1/2 and got 3.9*108. Seems to simple!?? any comments much appreciated