Axis Definition and 895 Threads

If I stretch an ellipse with .5 eccentricity along an axis 45 degrees from its major axis, doubling its area. How do I find the angle of the major axis of the resulting ellipse? Is there a simple rule based on the amount you stretch and the angle and orig eccentricity? Thanks.

Homework Statement A long, 1 kg uniform rod and 1.4 m length, is supported at the left end by a horizontal axis into the page and perpendicular to the rod. The right end is connected to the ceiling by a thin vertical thread so that the rod is horizontal. The thread is burned by a match...

Consider the line L(t)=<4t-1,2+2t>. Then L intersects: 1. the x-axis at point ____ when t=____ 2. the y-axis at point ____ when t=____ 3. the parabola y=x^2 at the points _____ and _____ when t=_____ and t=______ I am confused on how to approach this problem. Do I just make x=4t-1 and y=2+2t?

In coordinate geometry does x=o mean the y-axis or the yz plane!? ? ?

Homework Statement http://65.98.41.146/~grindc/SCREEN01.JPG Find the volume of the solid generated by evolving the region bounded by y = sqrt(x), y = 0, x = 4, when revolved around the line x = 6 Homework Equations The Disk/Washer Method - The Attempt at a Solution let R(y) =...

Hi all. i am integrating in MATLAB and plotting the results in a y-verically and t-horizontally. Matlab automatically plots y versus the time step which is great. but what i need to do is re-label the t-axis so the actual time appears instead of the time step- so instead of from 0 to 1200, it...

Homework Statement Find the volume of the solid obtained by rotating the region under the graph of y=1/x and y=1/x^2 about the vertical axis x=-1 Also given are points on the y-axis (0,2) and (0,5). I guessing these points are specific sections of the graphs where we find the volume...

Homework Statement Actually this is not a homework or course question, but I think it’s quite simple. So maybe it’s suited to post it here. I’m designing a machine that rotates a big object round its own axis. The object has a diameter of 2,7 meter and needs a torque of a least 105Nm to...

Homework Statement A = (1,1,-2) C = (0,1,-5) (in cartesian coordinates) Let A and C be drawn from a common origin and let C rotate about A with an angular velocity of 2 rad/s. Find the velocity of the head of C. Homework Equations v = w x r The Attempt at a Solution w = 2...

if i know a meter is observed at an altitude of 6km, to be traveling with an initial velocity of 20 km/s and the decelerating at a rate dv/dt=0.2km/s^2, which formula i should use to get the length of the semimajor axis of the meteor'orbit?

Homework Statement Find the angle between radius vector of the point M(6,2,9) and: a)x axis ; b)y axis ; c)z axis Homework Equations cos(\vec{a},\vec{b})=\frac{\vec{a} \vec{b}}{|\vec{a}||\vec{b}|} The Attempt at a Solution I tired with...

1. Ok here is a diagram I am HAVE NO IDEA HOW THE 30 DEGREES between the W force came and the radial axis! CAN sOMEONE SHOW ME or EXPLAIN PLZZz I suck at angles! http://img171.imageshack.us/img171/9158/50446152db6.jpg [/URL] W is acting DOWN

Hi, I need help or any sudgestions with the next scenario - I'm designing a sensor for a wind wave tunnel - can be found in the google search using the key words 'wind wave flume' The sensor should give me the speed and frequency of the cappilary gravity waves created in the tunnel by a...

Homework Statement A wheel of diameter of .68m roll without slipping. A point at the top of the wheel moves witha tangential speed of 5.4m/s. Whaat speed is the axle of the wheel moving? What is the angular speed of the wheel? How would i approach to do this problem, what equations would...

A wheel of diameter of .68m roll without slipping. A point at the top of the wheel moves witha tangential speed of 5.4m/s. Whaat speed is the axle of the wheel moving? What is the angular speed of the wheel? Can someone work this problem out, so i can see how its done. My teacher flies...

I remember an analogy with a child's spinning top, that does not rotate in a fixed axis but the axis makes a precessional movement. But the spinning top is sitting on something, it's getting a force from below that's not aligned with its weight, so this force has a torque, etc etc (can't...

Homework Statement Imagine a woman standing on a rotating disc (D) with a rotating wheel in her stretched arms (se picture here: http://image.vandrermodlyset.net/rotation.jpg ). The wheel is oriented in a horizontal plane, with the rotating axis (W) of the wheel parallel to that of the...

Im having a hard time getting my head around this, any help would be much appreciated. Homework Statement Determine the position of the centroid and calculate the second moment of area about a horizontal axis passing through the centroid for the following sections shown. Attached is the...

Homework Statement c) For such a "symmetric" object, prove that any axis going through the center of mass is a principal axis. Homework Equations The Attempt at a Solution I am not sure how they want me to prove this. I was looking at the Displacement Axis Thm but I am not sure...

Homework Statement What are the x and y components of a vector a in the xy plane if its direction is 230° counterclockwise from the positive direction of the x-axis and its magnitude is 2 m? Homework Equations The Attempt at a Solution My main issue is I'm not sure where...

Hi there, I'm an electrical engineering student currently building a 2 axis solar tracker. I need to build the frame and I'm posting here because I have no mechanical knowledge at all ... The system is basically two motors, each for each axis which rotates a small solar panel (one rotates...

... so that there are no seasons and it's spring forever? It would make many species go extinct. But is it possibly a good thing in the longer term? Imagine it's summer forever, like in Equador. Or spring forever, like in a flower conservatory. Is there anything wrong with this...

Homework Statement What angle is between function y=\sqrt{3}x and Ox axis? Homework Equations For example is logicaly clear that angle between function y=x is 45 degrees or \frac{\pi}{4} The Attempt at a Solution I just know that answer is \frac{\pi}{3}, but can't understand how...

Homework Statement Prove that on the axis of any parabola y^2 = 4ax there is a certain point K which has the property that,if a chord PQ of the parabola be drawn through it ,then \frac{1}{PK^2} + \frac{1}{QK^2} is same for all positions of the chord.Find aslo the coordinates of the point K...

Question: A space shuttle is in an orbit about the Earth. At its apogee, it uses thrusters and increases its velocity by 400 m/sec. What is the new orbit semimajor axis, eccentricity and how much will the next perigee altitude be increased? Known: Original semimajor axis: 7000 km -> a...

So I am asked to rotate by 45 degrees about the y-axis. With the power of the net i found that it is; [ cos(45) 0 sin (45); 0 1 0; -sin(45) 0 cos(45)] i really would like to understand HOW they get this. THANKS in advance!

Homework Statement Two particles having charges q1 = 0.600 nC and q2=5.50 nC are separated by a distance of 1.10 m. At what point along the line connecting the two charges is the total electric field due to the charges equal to zero? Homework Equations Coulomb's Law The Attempt...

I'm trying to understand how to find the axis of a helix but so far I seem to be hitting a blank. How for instance would I go about finding the axis of the helix r(t)=(e^t)costi+(e^t)sin(t)j+(e^t)k ? I would be very gratefull for any and all assistance.

Hi! More than a decade ago, I used to listen to a so-called walking encyclopedia over the radio. One of the radio listeners verified the information that he had read somewhere: That if the Earth revolved on its axis at a much faster rate, then time would become faster. However, this radio...

[SOLVED] Seriously? Moment of Force about a specified Axis So I really thought I understood this. I have attached the problem and attempt at solution. It should be easy to follow. Problem Attempt at Solution This was my process: 1. Write each F and each r as cartesian vectors 2. Find...

Homework Statement A thin, rectangular sheet of metal has a mass M and sides of length a and b. Use the parallel-axis theorem to calculate the moment of inertia of the sheet for an axis that is perpendicular to the plane of the sheet that passes through one corner of the sheet Homework...

i have an orientation of a 3d object in space given by theeta, si and phi i.e. angles which the objects makes with respect to three axis. Now i want to translate the problem such that i get an arbitrary axis rotation about which to some calculated degrees would produce same orientation...

Homework Statement Two thin rectangular sheets (0.23 m 0.35 m) are identical. In the first sheet the axis of rotation lies along the 0.23 m side, and in the second it lies along the 0.35 m side. The same torque is applied to each sheet. The first sheet, starting from rest, reaches its final...

Homework Statement I have to find the kinetic energy of the total system; b has mass 2m and a has mass m. They rotate around the y-axis and and through the origin (0,0). There's two ways of finding the kinetic energy of the system around the y-axis. 1) I find moment of inertia for each...

Hi Guys, I've attached 2 pages from the book of landau "The Classical Theory of fields", I have a question about the lorentz transformations in pages 10,11 after reaching the step: tanh(psy)= V/c How did he split the latter into sinh(psy) and cosh(psy) and added the "gamma" constant...

What I'm about to ask isn't a homework question, but it is a personal question relating to a home-project I'm working on. My question is, what is the moment of inertia of a hollow square tube about an axis perpendicular to its length? Here's a poor diagram: -----|----- (where | is the...

Homework Statement I have a problem that involves a vertical axis that can rotate through a fixed axis located at the very top of the rod, at point A (the axis is coming out towards us, the rod's rotation would look like a pendulum). The rod is nonuniform and there is a block attached to the...

Hi All: If given a set of 3D points data, it's very easy to calculate the covariance matrix and get the principle axises. And the eigenvalue will be the variance on the principle axis. I have a problem that if given a random direction, how do I calculate the variance of the data on the given...

hi there. can anyone please explain to me the parallel axis theorem? the parallel axis theorem states that I = I_cm + M(d^2) where d = distance from the center of mass axis to the parallel axis and M is the total mass of the object. The rotational inertia of a thin rod about the center is =...

Homework Statement A thin rectangular sheet of steel is 0.30m by 0.40m and has mass 0.470kg. Find the moment of inertia about an axis that is perpendicular to the plane of the sheet and that passes through one corner of the sheet. Homework Equations Parallel axis theorem: Ip = Icm +...

[SOLVED] 2 particles moving along x axis. Homework Statement Two particles move along the x axis. The position of particle 1 is given by x= (6.00m/s^2)t^2 + (3.0m/s)t + 2.00m the acceleration of particle 2 is given by: a = - (8.00 m / s^3) t and, at t = 0, its velocity is 20 m / s...

I got this problem and I got the answer 0.5 rad/s^2, but it is not the right one. pls help me. thanks At t=0 wheel rotating about a fixed axis at a constant angular acceleration has an angular velocity of 2 rad/s. Two seconds later it has turned 5 complete revolutions. What is the angular...

The question is: Plot a graph of the acceleration (vertical axis) as a function of the net force for the trials in which the mass remained constant. Draw a line of best fit and calculate its slope. What does the graph indicate about the relationship betweena cceleration and net force? What...

Suppose that a particle's position is given by the expression in the attachment Explain: 1. When does the particle first cross the negative x axis? 2. Find the particle's velocity as a function of time. Express your answer using unit vectors.(e.g., A i_unit+ B j_unit, where A and B...

Homework Statement A sphere consists of a solid wooden ball of uniform density 800 kg/m^3 and radius .20 m and is covered with a thin coating of lead full with area density 20 kg/m^2. A. calculate the moment of inertia of this sphere about an axis through the center. Homework Equations...

Hi Consider a symmetrical beam, where as we know the Neutral Axis (NA) would be at the Geometric Center. If that beam was simply supported at both ends, there would be equal tension and compression to ensure that beam was in equilibrium. Now if we applied a vertical load, downwards, in...

Homework Statement So I have been doing the adding of vectors by using their components and you are suppose to use the + X axis as a reference frame so when 3 vectors are given do you always have to subtract the given theta from the quardrant total ie. 22m, 56 degrees west of south plotting...

Homework Statement I've got a problem that I can't figure out. It deals with strain. I've got a box, sitting on the x-y axis(like normal x-y axis's are). The box extends 4 inches from the origin in the x direction, and 2 inches up. Going clockwise(starting at origin) the corners are...

Homework Statement The region in the second quadrant bounded above by the curve y=-x^3, below by the x-axis, and on the left by the line x=-1, about the line x=-2 Homework Equations It's basically the big radius squared minus the small radius squared, integrated in terms of y, and...

Hi everyone, I'm pretty new to Physics Forums but it seems like a fairly friendly community. :) Homework Statement Determine the equation of the surface formed when the line x=3y is rotated about the x-axis. Homework Equations x=3y is the given line.The Attempt at a Solution First I...