Movement Definition and 637 Threads

I'm no physicist, but I just have some questions... 1) The universe is expanding, correct? This means that its centre of mass is constantly changing, and the centre of the universe is also constantly changing (well... if the universe is spherical, and was increasing in proportion to a...

Hi all, I hear all this talk about how open source is awesome and how software should be free and accessible to anyone. While I do enjoy gaining access to free software and whatnot, I can't help but wonder, how do software developers actually make money if the open source thing catches on...

say there was no wind at all, no air movement. would your clothes still dry?

Hi, could some one please explain in detail why this things are true? thanks A simple pendulum suspended in a rocket ship has a period T0. Assume that the rocket ship is near the Earth in a uniform gravitational field. True: If the ship accelerates downward at 9.81 m/s2, the pendulum...

Homework Statement A Girl is swinging on a maypole in a playground. The Girl has a mass of 36Kg and, when she is moving with speed of 2.0m/s, the light rope makes an angle of 20 Degrees with the vertical. Consider the motion of the center of mass of the girl, which movies in a circle of radius...

Hi everybody. I am a mechanical engineer trying to do an electrical experiment. I wonder if anybody can help me with an advice. Here is my experiment. I have a single rectangular metal plate to which I apply a known high negative voltage DC. Not sure yet what that voltage is going to be...

My thing is Movement,and Gravity ,plus their relationship with Kinetic energy. With the right pattern of movement I think gravity can be neutralised. I am working with loudspeakers which provide the movement, this appears as vibration and can be transferred to any material .The idea...

Does a elemental particle move through all points along a vector or does it move in "ticks" of a finite quanta? Or in terms of waves and probability, if we measure the location of a particle at a certian time, will the particle be evenly distributed along all possible points of its vector...

Hello, sorry for my English:D Homework Statement I am trying to find motion equations for a mass moving around a big mass (ex. planet around sun), assumption is that the mass in middle is static (so this can be reduced to moving of mass around central force in middle of cartesian system), and...

Here is an excerpt from a book: Notice also how the charged particle is captured by the magnetic field, just drifting along the field direction. In my book, the field direction is in the y-direction, but the in addition to the particle having an initial y velocity, it had an initial z velocity...

Hi guys Let a single cylinder ic engine. Now when we start the engine , then depending upon the position of crank the last time we switched off the engine, it is possible it may rotate in reverse direction because piston just has to reciprocate so acco to crank position at rest it may move...

As somebody with considerable immunological knowledge and a great interest in the field, I am very curious to see what evidence is in support of the anti-vaccine movement. Personally, I believe in the practice of vaccination because of what I have learned regarding the human immune system...

Hi guys, Im trying to create a simple application for a college project based on an egg moving around a level plane. I've looked around and I've been finding it very difficult to find any equations to simulate the movement of an egg. If anyone has any ideas or could point me in the right...

Ok, I know this post is not up to specs but the real problem with this is my trouble with calculus and derivatives (I'm actually worse at that than at English ;) ) in general. I only need help with this step of the homework (basic math help). This describes the movement of the point: x=...

Homework Statement A 45.0-kg woman stands up in a 60.0-kg canoe 5.00 m long. She walks from a point 1.00 m from one end to a point 1.00 m from the other end. If you ignore resistance to motion of the canoe in the water, how far does the canoe move during this process? Homework...

A car is traveling at 40.7 mi/h on a horizontal highway. The acceleration of gravity is 9.8 m/s/s. If the coefficient of friction between road and tires on a rainy day is 0.12, what is the minimum distance in which the car will stop? (1 mi = 1.609 km) So given: vi(initial velocity): 40.7...

Homework Statement A cylindrically shaped space station is rotating about the axis of the cylinder to create artificial gravity. The radius of the cylinder is 82.5 m. The moment of inertia of the station without people is 3.00 x 10^9 kg m^2. Suppose 500 people, with an average mass of 70.0 kg...

Movement of particles in Magnetic Field, Need help! Homework Statement http://img132.imageshack.us/img132/9773/81045485.jpg Homework Equations The Attempt at a Solution i need someone to confirm if this is right... 1) B 3)C<B<A For the first one, my friend said it's A,because...

Hi I am struglling to work out the expression for theta=f(x) for a piston, that moves linearly by a distance of x along the inside of the cylinder, and is attached to a conrod of length l, whose other end is at a radius r on a fly wheel. I want an expression for the angle theta that the fly...

Homework Statement The train travels from place A to place B for one hour. Forty minutes after the departure, first train meets with second train, which departed from place B ten minutes after first train, and it’s traveling with an average speed of 40 km / h. Homework Equations What...

[b]1. A particle moves in such a way that its position z, in meters, is given as a function of t, in seconds, by the equation z = 2.12m/s^2t^2 - 2.96m/s^3t^3 What is the velocity (m/s) of the particle at t = 0.657s The answer is -1.05, which is not what I got. [b]2. First, I used the...

Hi people, I am pretty desperate because I have not the least idea of how to do two questions on my homework which is due for tomorrow..Please take a look and if you could do them, that's great, and if you could bother to explain them to me, i will appreciate it a lot! Thank you! and here are...

Complex Numbers Proof Multiplying the top and bottom by the complex conj. of the bottom: \frac{a+ib}{c+id} * \frac{c-id}{c-id} Gives me: \frac{(ac+bd) - i(ad-bc)}{c^{2}+d^{2}} In form x+iy it is: \frac{(ac+bd)}{c^{2}+d^{2}} + (\frac{(bc-ad)}{c^{2}+d^{2}})*i This is where...

Homework Statement A particle moves so that its position (in meters) as a function of time (in seconds) is R= ln(1+t)i+ (et-1)j + tk . Write expressions for (a) x-, (b) y- and (c) z-components of its velocity as well as the (d) x-, (e) y- and (f) z-components of its acceleration as functions...

Hello! Anyone out there that can explain the helium model? Movement of electrons, forces, speed, etc? In an non excited atom.

Please look into this site http://knol.google.com/k/alex-belov/paradox-of-classical-mechanics-2/1xmqm1l0s4ys/9# The experiment 2 animations This is animation based on classical mechnics laws http://mysite.verizon.net/vze27vxm/sim.gif This is animation based on theory of...

Tomorrow, you may or may not be aware, is the date of Glenn Beck's 9/12 Project, which the Fox News host http://tunedin.blogs.time.com/2009/09/11/dont-tell-me-what-912-means-glenn-beck/

in the following question, http://62.90.118.184/Index.asp?CategoryID=318 i am given the following only: angle of the cord = \alpha angular velocity = \omega and am asked to find the radius what i did was : Newtons 2nd on the radial and "y" axis Fy=T*cos(\alpha)-mg=0 (T being...

Homework Statement A certain elevator cab has a total run of 197 m and a maximum speed is 307 m/min, and it accelerates from rest and then back to rest at 1.21 m/s2. (a) How far does the cab move while accelerating to full speed from rest? (b) How long does it take to make the nonstop 197 m...

Homework Statement A baseball, with mass m = 0.145 kg, is thrown directly upward from z(0) = 0 m, with initial speed v(0) = 45 m/s. The air drag on the ball is given by Cv2, C = 0.0013 Ns2/m2. Set up a diff. eq. for the ball's movement and solve it for both v(t) and z(t). m = 0.145 kg C =...

My question is what causes death wobble? Let me explain more... The vehicle I've experienced this on is a Jeep with a solid front axle, but it can happen on other vehicles. While driving down the road at say 50mph, I hit a small bump, and the steering wheel and tires shake side to side...

Hiya, I'm currently reading The Encyclopaedia Britannica Guide to the Brain and I came across a statement about the precentral gyrus that I'd like to find corroboration for: "When parts of the gyrus are electrically stimulated in conscious patients (under local anaesthesia), they produce...

How would you do it if you were given initial x y z components of the object known as position vector and velocity vector of the object. Gravity is -981 in my case.

Hope you guys can help me in solving this problem... There one grooved surface seal the another smooth surface from bottom ... inside the grooved surface there will be a liquid... this grooved surface will rotate at certain speed , while the smooth surface on the bottom will remain...

would anybody like to discuss how to accurately follow a particle moving in a HELICAL PATHWAY using vectors, spherical and cylindrical coordinates? I'm not sure how to follow a geometric helical pathway using linear and parametric equations.

As a school project I was assigned to measure the swing of a pendulum. At the time I was doing the experiment I found it almost impossible to prevent the pendulum from moving in an ellipse, at first i describe the elliptical movement as a source of error, but then it occurred to me that it might...

Calculating wind load is wind speed squared x .00431 x area in sq. ft. A 5 mph wind with a vertical 100 sq. ft. wing is 10.77 lbs. The mass of salt water is around 854 times greater than the mass of air. Can you use the wind formula and multiply by 854? Does the weight of water at different...

Calculating wind load is windspeed x itself x.00431 x sq. ft. of area. A 100 sq.ft vertical wing in a five mph wind is 10.77 lbs. The mass of salt water is around 854 times that of air. Can you use the wind formula and multiply by 854? Also, does this change with the weight of water at different...

hi folks, maybe somebody can help me with this: According to the standard theories of cosmology, the universe started with a "Big Bang" about 14 thousand million years ago and has been expanding ever since. Yet there is no centre to the expansion; it is the same everywhere. The Big Bang...

Help needed with the effect of "no time"/"time freeze" on bullet movement 1.There is a special question in our assignment:Assuming a person is able to freeze time, will he be able to shoot a bullet from a gun? 2. There are no real equations I know except for the standard distance = speed X...

Does everything move incrementally at the speed of light?

Stupid question (or maybe stupid asker), but I'm having a hard time finding an answer. Of course the movement of electrons (- charge particle) creates a magnetic field when moving steadily through a conductor but what about protons (+ charge particle)? Let's just imagine you have protons passing...

A common thought after one learns about the limit of the speed of light is that a long rod when pushed would seem to cause the other end to move instantly, thus carrying information faster than light. The reason this isn't the case is because the movement will only travel through the rod at the...

1. There are two 50 kg skaters in a friction-less horizontal surface. Both have velocities of |V|=10 m/s, in opossite directions (that is, skater 1's velocity is 10 m/s i, while skater 2's velocity is -10 m/s i). They both skate parallel to each other with a distance of 1,5m. Skater 1 has a...

Not sure if this should go here or in the relativity forum... let me know if I need to move it. I was reading something, and it said this: "A photon also has a rest mass, which is zero, even though a photon is always moving at the speed of light, and so is never at rest. But if an observer...

Any idea about how determine body movement upon the accelerations? Hi, I am trying to implement an algorithm which would determine the person's activity upon the received acceleration measurement data. I am measuring the accelerations using accelerometer sensors on mobile phones and send...

Does quantum mechanical definition of momentum require "movement"? If quantum mechanical definition of momentum does not require "movement", then why "white dwarf star" won't collapse? How can it resist the pressure of gravity in the star? http://en.wikipedia.org/wiki/White_dwarf

Homework Statement A hiker shouts toward a vertical cliff 735 m away. The echo is heard 4.00 s later. (a) What is the speed of sound of the hiker's voice in air? [] m/s (b) The wavelength of the sound is 0.732 m. What is its frequency? [] Hz (c) What is the period of the wave? [] ms...

Homework Statement A point moves with constant speed (value) over a sphere, following the curve defined by: f = t = l For t=0, the point is at (t,f) = (0,0) and for t=3 it's at (pi/4, pi/4). How long does it take to reach the north pole of the sphere? Homework Equations The parametric...

Homework Statement In a lighthouse that is 2km from the shore, the searchlight rotates clockwise once every 50s. How fast is the spot of light on the shore moving: a) When it's directly opposite the island? b) When it is 1km from the point opposite the island? Homework Equations...