What is Spinning: Definition and 579 Discussions

Homework Statement {Number 5 on attachment. It has picture.} When a spinning bike wheel is placed hor- izontally, hung from a pivot at one end, the axis of rotation of the wheel will swing in a horizontal circle. In which direction does it turn (as viewed from above)? 1. downward...

I was thinking about ways to test relativity, and time dilation. The idea popped in my head of designing something, housing a clock, with the intention of getting it to spin in the vacuum of space, as fast as possible, and observe the difference in time. Is this feasible? Has this...

Lets say we have a spherical shaped and very powerful magnet. Let's say it has a 3" diameter and has some good weight to it. What would happen if you spun the magnet at great speeds. Let's say for the sake of argument say some 300,000 RPM. Could the centrifugal for created by the spinning...

Of, so the Earth has gravity because of its mass, but what does the effect of the spinning of the Earth cause on gravity. Wouldn't thinking about centrifugal force make you think that the extreme speed we are spinning mixed with how far we are from center have some effect on us out on the edge...

When you have a spinning top undergoing forced precession (due to the torque created by its weight trying to tip it), you seem to get two precession rates. Why? I get this result from using Euler's equations, specifically that the sum of moments tipping the top is (in the case of steady...

Homework Statement A coin is off-center on a turntable which is spinning at a constant velocity. The coin is not slipping. From what I have gathered, the radial acceleration of the coin is caused by the force of static friction on the coin. There is no tangential acceleration. Homework...

I posted this in the Intro physics sections, but then realized that spherical coords might be a bit complex for introductory physics. This has been bothering my head for a couple days now. Any help is appreciated. Given: A wheel of radius R rotates with an angular velocity. The wheel lies in...

Homework Statement A 5.10 coin is placed 16.0 from the center of a turntable. The coin has static and kinetic coefficients of friction with the turntable surface of = 0.810 and = 0.510. What is the maximum angular velocity with which the turntable can spin without the coin sliding...

Hello, I would like to know how to determine the max RPM of a disc. I would think it would be the centrifugal force against the Yeild Strength. Any help would be appreciated. Thanks, Ron

Homework Statement A satellite is spinning clockwise and has four low-mass panels sticking out. A tiny meteor rips through one of the panels and continues in the same direction, but with reduced speed. Afterward, calculate vx and vy components of the center-mass velocity of the satellite. Here...

Hello, I have a question about a spinning symmetric top: When the equations of motion are solved, they are solved in two frames--the space frame and the body frame. I understand the space frame, but in the body frame you are looking at the top from a frame that is rotating with it, right? So...

If 2 balls or cylinders with watches inside were spun one at close to the speed of light, the other at half the speed of light, both with clocks or timers in them; would they show different times when stopped after having been spun for a certain length of time. I'd presume if they were made...

what would the affects of a faster and faster spinning Earth be gravitationally? Mass increases with rotation i believe? If rotation neared the speed of light how much would the mass and gravity change? I am wondering what is more significant, the gravitational affects or the centifugal...

Homework Statement Show, by conservation of energy, that when a length, L, of string has unwound that a yo-yo is spinnning with angular velocity Remember the yo-yo has both linear and rotational velocity Homework Equations \omega= \sqrt{}gL/R^{2} The Attempt at a Solution I do...

If a dancer who balances on one leg starts spinning, is having the center of mass above the point of contact enough, or does he need to assume a special shape? I mean is the moment of inertia important provided the point of contact (feet) are not slipping?

Hey guys, I have this really annoying last question on my assignment which is a pain. It combines 3 physics principles together. I am having problems specifically with 2) 3) and 4) 2)I know that T = | r x F |, but what kind of general vector do I use to represent F? 4) I have no...

Homework Statement At t=0, a grinding wheel has omega=24.0rad/s, alpha=30.0rad/s^2 until a circuit breaker trips at t=2s. From then on it turns through 432rad as it coasts to a stop at constant alpha. a) through what total angle did the wheel turn between t=0 and the time it stopped? b) what...

Does anyone have the explanation for the spinning, levitating orbiting card trick ?

Imagine a drum that is 1m in diameter and .5m long made of 10mm thick steel (369Kg). The drum is stabalized by an adequate gyroscope (50Kg) attached to the outside. Oriantate the drum so that it appears as a circle in front of you. The cylinder portion of this drum is modified so that 980cm...

Hello; What happens if you took a compass and surrounded it completely with north poles (and no south poles)? Would the compass just spin repeatedly because it doesn't know what to point to? Also, the compass can't spin forever; so I'm guessing it will stop because the magnets can't last...

A friend and I are having a debate on this and I just need to know yes or no, and why?

In the Richard Feynman book QCD, he talks of the chance of reflection of a light photon off water varies from 0% to 8% (depending on the width of the layer). He says that the probability changes 36000 times per inch for red light without showing how it is done (ie. how he got the 36000...

Since there is no friction on a super fluid, can they be spun faster and faster until they reach relativistic speeds? I'm not totally sure the method you would use to spin the fluid, possibly electromagnatism somehow but assuming it were possible.

Homework Statement A 45 kg figure skater is spinning on the toes of her skates at 1.0 rev/s. Her arms are outstretched as far as they will go. In this orientation, the skater can be modeled as a cylindrical torso (40 kg, 20 cm average diameter, 160 cm tall) plus two rod-like arms (2.5 kg each...

Homework Statement If a spinning drum ride cannot exceed a 10 m radius, and the riders are not to experience an acceleration greater than 2g, what is the maximum speed at which the drum can spin? Homework Equations No Idea The Attempt at a Solution I tried using (theta) = tan-1...

Hello, I'm a long time stalker but recently decided to register in this website. I'm have to make an Extended Essay and I decided to do it in Physics and I thought it would be interesting to investigate the spin on a football (soccer ball) when kicked depending on the location of the foot...

Does the direction a galaxy is spinning have anything to do with some cosmic Coriolis effect?

1. At a county fair there is a betting game that involves a spinning wheel. As the drawing shows, the wheel is set into rotational motion with the beginning of the angular section labeled "1" at the marker at the top of the wheel. The wheel then decelerates and eventually comes to a halt on one...

Homework Statement A wooden rod of negligible mass and length 77.0 cm is pivoted about a horizontal axis through its center. A white rat with mass 0.480 kg clings to one end of the stick and a mouse with mass 0.180 kg is placed at the other end of the rod (the end away from the rat), and the...

Block inside a spinning cone -- Newton's 2nd Law problem Homework Statement See attempt at solution. I have attached everything there.Homework Equations F_net = m * a_n (net force) W = mg (weight) a_n = 4*pi^2 * R * f^2 ... formula for "normal" component of acceleration where R = radius, f =...

Assumptions: 2D problem only, no gravity, no friction, no external torque. Flat circular disk spinning at a constant angular velocity w. Disk is initially at (0,0), but is NOT restrained in translation. Disk has some finite mass. A small ball (finite mass) is tethered to a string which...

Homework Statement You have a solid, homogenous ball with radius R. Before falling to the floor, its center of mass is at rest, but it is spinning with angular velocity \omega_0 about a horizontal axis through its center. The lowest point of the ball is at a height h above the floor. When...

Years ago they showed on TV, that spinning superconductors sort of shield gravitational field. Now I read http://news.softpedia.com/news/The-First-Test-That-Proves-General-Theory-of-Relativity-Wrong-20259.shtml How serious is this to be taken?

1. a clever engineer solves the high velocity exploding flywheel problem (structure fails) and any other serial problems. 2. therefore a bench top a. torus, b. disk, c. cylinder spinning about its axis with a tip speed approaching c 3. what will happen to space time and gravity or anything...

Hey, I was reading a book about dark matter and how it could be the cause of our universe to be expanding. However, from what I understand dark matter has not been "discovered" yet. Well I was thinking if our universe was spinning then could the centripetal acceleration caused by the...

Hey, I'm new here, so I hope this hasn't already been posted, but I really need help with this question. There is a commonly used example to show how Einstein helped prove General Relativity through space curving due to different ratios in radians of a spinning wheel made to spin at the velocity...

Homework Statement A ball is going around in a circle of radius 5 m. It starts from rest, and goes through an angle change of 26 rad in 5 seconds. The ball weighs 0.3 kg. Find its moment of inertia, and find the torque about the origin. Homework Equations The Attempt at a...

If you spin on a chair with your arms and legs out and then pull them in, your rotation accelerates. What torque is responsible for that acceleration? It seems to me all the movement is towards the axis of rotation and should not be responsible for any torque. In fact, take an idealized body...

Here's a question that I thought up while shooting darts through a five-bladed ceiling fan. I'm lazy, so I'll use symbols for the constants in the equation. Say I have a five-bladed fan of radius R, with a blade width W, spinning at angular velocity V. I shoot a dart of length L through the...

Homework Statement I need a quick sanity check here please. (Sorry, my alphas keep coming out as power signs, they're not!). To find the force to slow a spinning disc with known moment of inertia (0.0004kgm2) and known angular velocity (120pi rad/s) to a stop in 6s. Here, the...

The trick is to see this lady spinning in each direction: clockwise or counterclockwise. Most will see it orienting in one direction only. It's difficult to switch it in our minds. For many the task will be impossible. http://mindbluff.com/clockwise.htm

I'm trying to figure out what is the resulting motion when a ball collides with a spinning ring whose center of mass is initially at rest. See attached diagrams. The collision is assumed to be elastic. The ball has unit mass, and the ring has unit mass and unit radius. Shown in the "before...

Hi Everyone, There is something I am having trouble I am understanding. Why does a spinning propeller cause a plan to yaw while it is taxiing? Also, how does the flow behind a propeller effect the performance of the control surfaces on the tail? Does it have any effect? Because the flow...

Homework Statement im doing a sipnnig top question and i have got an answer for the precession angular velocity this site shows a good example of what i did: http://hyperphysics.phy-astr.gsu.edu/hbase/top.html and so i have gr/K2w if i sub in I=mK2 but i need to find the angular...

A 2.0 kg, 1.0 m long rigistic plastic rod is spinning about its center of mas at 2.1 rad/s. What is the magnitude of torque that will bring the rod to a halt in 5.0 s? A.) 0.07 N*m B.) 0.13 N*m C.) 0.21 N*m If you could help me set up the proper equation to use, I would greatly...

Homework Statement A bead of mass m and charge q is placed on a frictionless, rigid rod that is spun about at one end at a constant rate w on the xy plane. There is a constant magnetic field in space B = B_0\hat{z} Homework Equations Write the Lagrangian for the system, use the generalized...

I have an application (clothes washer) which requires a drive design such that: The drum contains 170 lbs of water and clothes, spinning at 95 rpm. The drum spins at this speed for 1 second, then decelerates for 0.25 seconds and reverses direction. This process repeats for 30 minutes...

Suppose you have a symmetric top precessing and nutating under the torque due to gravity. My question is this: does the spin rate of the top (the rate at which it spins on its axis of symmetry) vary with time or is it constant? I am assuming the 'foot' of the top is fixed and that the motion...

Homework Statement so I am doing a project where we need to invent something and we have our idea and we are working towards a clear focused idea put we hit a bump in the road I need to know if there is any possible way to have this scenario work... Inside a tire in two tubes, one for air...

Mass being dropped on spinning disk problem NEED HELP! 1. A disk has a radius of 1.25m and a mass of 10kg. It lies flat on a smooth table and is spinning with an initial velocity of 10 rad/s about a pin at its center. A 5kg mass is dropped on it at a distance of 0.50m from its center. Find...