Rotational Definition and 1000 Threads

Hello everyone, Please help me with this problem, as I am getting stuck solving this problem. A solid sphere of Mass M and Radius R rolling (pure) encounters a protrusion on the surface of height R/4. Its in the form of a step. What can be the maximum velocity V of...

Homework Statement I cannot get the answer for part c, -13.02rad/s^2 The Attempt at a Solution 52.08=260.42+α(10) -208.34=10α α= -20.83rad/s^2 (Correct) 0=52.08+α(10) -52.08=10α α=-5.208rad/s^2 (Wrong) Please help, thanks..

Two solid cylinders p and Q of same mass and same radius start rolling down a fixed inclinded plane from the same height at the asme time.cylinder P has most of its mass concentrated near its surface while Q HAS MOST of its mass near the axis... THEN 1)WHICH HAS MORE MOMENT OF INERTIA AND...

Homework Statement Since Gear A -------- Vi=0 t=12s θ=40∏ as given in the question, can I assume that Vi=0 t=12s for Gear B/Drum C as well? If not why? Thanks..

Forgive ne if this sounds stupid but does GR take into account angular momentum, torsion, and other effects of rotation? The stress energy tensor doeznt appear to have any terns that are meant two accommodate angular momentum abd rotational stress.

Hello I've attached the problem. Any help would be greatly appreciated. I understand that by giving us the clue of rotational equilibrium, it means net T has to be 0. The force at 10N will cause clockwise torque (T= rF, so T = .04m * 10N). The thing that confuses me is the force at point...

Homework Statement I am writing a large paper on the physics of fishing and would like to know what equation would prove the statement that a longer fishing pole would result in a higher velocity of the lure? My physics book gives me a gamut of equations for rotational motion but I can't...

Homework Statement The problem is attached as an image. Note this is from a past exam. Homework Equations Conservation of angular momentum. Rotational kinetic energy. The Attempt at a Solution a) The moment of inertia of the man and stool is given as 3 kg m^2, and the dumbells...

http://img444.imageshack.us/img444/8148/rollwx.jpg A rope is wound around a cylinder of mass 4kg, and I=0.02kg.m2 about the cylinder axis. The frictional force between table and cylinder is negligible. Solution: a=20/4=5.0m/s2 α=ar is not applicable when slippage occurs. My...

I have a question regarding angular momentum and rot kinetic energy. For example, if angular momentum is conserved, and the radius is cut in half, then moment of inertia is reduced by a fourth, which will result in increase in angular velocity by factor of 4. My question is why is the...

Hey guys! Ok, so I don't have that much to work with, and I am sorry for my lack of detail, but my memory is a bit fuzzy. I had to do a problem like this for my physics test yesturday: On the test we were given a problem involving a roller coaster (Rotating Drum of Death was its name)...

Homework Statement Attached 1st pic is the question, 2nd pic is the formula PS: I am sorry if i have posted on the wrong section. The Attempt at a Solution My understanding for this question is for compound pulley, angular velocity is the same, linear velocity is different. For pulleys in...

Hi guys, I have a few doubts on Rotational Motion and hope someone can help me out. This 3 formula is for finding angular velocity, angular acceleration and angular displacement right? ω=ωi+αt ω²=ωi²+2αδ δ=ωit+1/2αt² And this 3 formula is for finding the linear...

1) When there is no friction , a wheel with a Vcm = X m/s will only be slipping across the surface at a constant velocity.It won't be rotating because there will not be any forces creating torque. 2) The system ( composed of the rotating object ) always tries to find a balance between...

Hi all, first year MechEng student here, final question of the final assignment of the year, would appreciate any assistance: Homework Statement A 0.150 kg yo-yo has an outer radius R that is 5.60 times greater than the radius r of its axle. The yo-yo is in equilibrium if a mass m is...

And if so, what is the limit? Some pulsars spin very fast. more than 700 times per second, or even faster? So the centrifugal force would be very strong at the equator, threatening to rip them apart. Is there a limit on how fast a pulsar can spin before the centrifugal force would...

Since the HCl molecule has a non vanishing dipole moment, it is allowed to have pure rotational spectrum. If I understand this correctly then it's possible to excite the molecule in such a way that its vibrational energy stays the same while its rotational energy increases by some amount. This...

Homework Statement A spinning disk is rotating at a rate of 30 rad/s in the counterclockwise direction. The disk is slowing down at a rate of 6 rad/s2. Find the angle through which the disk has turned after 3 s in radians, degrees, and revolutions. Homework Equations θ=θi + ωi*t + αt^2...

Homework Statement Engineers are designing a system by which a falling mass m imparts kinetic energy to a rotating uniform drum to which it is attached by thin, very light wire wrapped around the rim of the drum. There is no appreciable friction in the axle of the drum, and everything starts...

I want to ask why a rod's rotational inertia with rotational axis at its end is not 1/2 mR2 but 1/3 mR2?

1. Electric toothbrushes can be effective in removing dental plaque. One model consists of a head 1.1 cm in diameter that rotates back and forth through a 70.0 angle 7600 times per minute. The rim of the head contains a thin row of bristles. (See the figure )Assuming that the toothbrush has...

Homework Statement You attach a mass M to a string and wind the string around the circumference of a wheel. The wheel has two hubs with radii R1 and R2 with R2 > R1. You perform two experiments. First you wind the string around the smaller radius wheel and allow the mass to fall a distance...

This is my first post on here; I hope it will be worth it. I haven't been able to find an adequate solution to this elsewhere. Homework Statement A 5.30 kg ball is dropped from a height of 11.5 m above one end of a uniform bar that pivots at its center. The bar has mass 8.50 kg and is 9.00 m...

Homework Statement A thin, uniform 3.60kg bar has two balls glued on either end, each with a weight of 2.5kg. The length of the rod is 90cm and is balanced in the center. When one ball falls off calculate the angular acceleration just after this happens. (e.g the rod is falling in a...

Homework Statement A string is wrapped several times around the rim of a small hoop with radius 8.00 and mass 0.180 . The free end of the string is held in place and the hoop is released from rest. After the hoop has descended 95.0 , calculate the angular speed and speed of its center...

A massless string is wrapped around the equator of a solid sphere (mass M = 76.2 kg, radius R = 0.211 m). A girl holds the free end of the string, and the sphere is released from rest, Assume: - the sphere is always parallel to the floor - the string is always perpendicular to the radius of...

Hi Is "orbital velocity" supposed to be the same as "rotational velocity"? it seems that a "rotation curve" is supposed to plot the rotational velocity of a star, but then some articles e.g. http://en.wikipedia.org/wiki/Galaxy_rotation_problem claim "orbital speed" is plotted. The equation...

Hi Is "orbital velocity" supposed to be the same as "rotational velocity"? it seems that a "rotation curve" is supposed to plot the rotational velocity of a star, but then some articles e.g. http://en.wikipedia.org/wiki/Galaxy_rotation_problem claim "orbital speed" is plotted. The equation...

Homework Statement A wheel starts from rest and accelerates uniformly to 200rpm in 6s. After it has been rotating for some time at this speed, the brakes are applied and it takes 5 minutes to stop the wheel. If the total number of revolutions is 3100, calculate the total time of rotation...

Homework Statement An object, consisting of two point masses with mass m are connected by a rigid shaft with negligible mass. They are lying horizontally at rest. One of the point masses is instantly given a speed of v. Calculate the total energy of the system once the system has stopped...

A string is wrapped around a disk of mass 2.1 kg (it's density doesn't have to be uniform). From rest, you pull the string with a constant force of 9 N. At this instant, the center of mass has moved 0.11 m, and your hand has moved 0.28 m. 1. At this instant, how much rotational kinetic...

Homework Statement You are asked to measure the moment of inertia of a large wheel, for rotation about an axis through its center. You measure the diameter of the wheel to be 0.740 m and find that it weighs 280 N (note, that's not the mass!). You mount the wheel, using frictionless...

What is the equation that relates the angular velocity of an alternator rotor with its output electrical power, voltage and frequency (not necessarily just one equation) . And for a DC generator? I know that when you calculate the power generated by a turbine you multiply its efficiency of...

Homework Statement A particle of mass m rotates with a uniform speed on the inside of a bowl's parabolic frictionless surface in a horizontal circle of radius R=0.4 meters as shown below. At the position of the particle the surface makes an angle θ=20 degrees with the vertical. The angular...

Hello there! Im studying microwave spectroscopy, and I'm stuck because I don't see why the spacing between rotational energy levels increases as J does. Can anyone explain please? Also, about IR, I see everywhere that the selction rule is Δv=±1. Correct me if I'm wrong but I'm guessing...

Homework Statement A uniform disk with mass m = 9.32 kg and radius R = 1.37 m lies in the x-y plane and centered at the origin. Three forces act in the +y-direction on the disk: 1) a force 340 N at the edge of the disk on the +x-axis, 2) a force 340 N at the edge of the disk on the –y-axis...

a) suppose we tie a ball with a string and rotate it keeping its other end tied with one of our fingers then the only external force acting on it is the tension. Which force then cancells 'mg' acting vertically downward? b) if a mass is rotating in a circular path then in which direction does...

Is it the same as the total angular momentum quantum number ?

When a ruler is placed on a pivot and I push it down from one side, then there is a moment. But then is there any linear movement? Since there is no translational equilibrium then won't there be a linear motion? Then how does rotational equilibrium come into play here?

Homework Statement A mass M slides down a smooth surface from height h and collides inelastically with the lower end of a rod that is free to rotate about a fixed axis at P as shown below. The mass of the rod is also M, the length is L, and the moment of inertia about P is ML2/3. The angular...

Thinking about rotating mass (for example a bike tire) and the disadvantages / advantages that come with differing weights/masses. Most everybody you speak to are programmed to think that a lighter tire will require less energy, thus, everyone tries to find the lightest tire possible...

We are doing rotational volume in Calculus II right now. I know the basic rules for the disk, washer, and shell methods, but I'm having trouble getting started with these questions. I'm not sure how to set up the equations. Any sort of help would be great. Thanks so much!

Hey, We saw in class that rotating a spin state with an angle of 2pi returns minus the state, and so it has to be rotated 4pi rad in order to return to the original state. However, we also saw that the expected value of the spin DOES return to its original value after a rotation of 2pi rad...

rotational motion and moment of inertia---HELP! Homework Statement Two masses m1=2.00 kg and m2=1.00 kg are linked by a thread and thrown over a pulley whose mass is 1.00 kg. The radius of the pulley is 0.200 m. a) Find the acceleration a with which the weights move b) the tensions T1...

This is an example problem I am studying from a classical mechanics textbook. Wrap a light, flexible cable around a solid cylinder with mass M and radius R. The cylinder rotates with negligible friction about a stationary horizontal axis. Tie the free end of the cable to a block of mass m and...

Homework Statement Imagine a system consisting of a chain that runs over two sprockets. The chain rotates around the sprockets with a constant linear velocity (i.e. the chain is taut and rigid). The front sprocket has a radius rfront and an angular speed ωfront and the rear sprocket has a...

Homework Statement A diatomic molecule can be modeled as two point masses, m1 and m2, slightly separated. If the molecule is oriented along the y-axis, it has kinetic energy K when it spins about the x-axis. What will its kinetic energy (in terms of K) be if it spins at the same angular...

Homework Statement Which of the following formulas is valid if the angular acceleration of an object is not constant? Explain your reasoning in each case. (a) v = rω; (b) atan = r\alpha; (c) ω = ω0 + \alphat; (d) arad = rω2; (e) K = 0.5Iω2. Homework Equations The Attempt at a...

Homework Statement A 4 kg block, 10m above the ground is attached to a long cord which is wrapped around a 1050 g iron disc of radius 40 cm. The system is originally at rest, afterwards the block is let go and allowed to fall. From the time the block is let go to when the block crashes with...

Homework Statement http://imageshack.us/photo/my-images/545/rotacion1.jpg/ Translation: Determinate, for the system of Fig. 10-39 the angular velocity of the disk and the linear velocity of m and m'. Calculate the tension in each string. Suposse that m = 600 g, m' = 500 g, M = 800 g, R = 8...