Angular Definition and 999 Threads

Homework Statement Consider two forces F and -F that act at different points on an extended object. Show that the net force of this combination is zero and that the torque about any point P is independent of the location of P, and depends only on the separation of the two points at which the...

I've been a fan of this forum for a while, but never signed up for it, today I'm stuck on this problem and can't find anywhere other than Chegg but I don't have a premium account. 1. Homework Statement A meter stick is at rest on frictionless surface. A hockey puck is going towards the 30cm...

Homework Statement A homogeneous cylinder of mass 1.20 kg and diameter 25 cm rolls down an inclined plane that makes an angle of 25 degrees with the horizontal. What is the speed of the axis of the cylinder by the time the cylinder has rolled 1.00 m down the plane? Homework EquationsThe...

Hello, i have some problems with the ergosphere of a rotating black hole. I can show that an object must rotate with the black hole and a can determine the intervall of possible velocitys. But is it possible to calculate the exact velocity? How it depends on the initial velocity of the...

Homework Statement A thin ring of radius r is constrained to rotate with constant angular velocity ω as shown in attached picture. Let the linear mass density of the ring be ρ(θ)=ρ0(2+sin2θ) where ρ0 is constant. a) Find the angular momentum L of the ring about O, at the instant the ring is in...

I was going through Periodic Motion chapter of my book and came across an equation while defining the relation between Time Period of on oscillating particle and force constant. k/m=w2 which was applied in, T = 2xpie/angular velocity can anyone please help me define this equation. I can't seem...

Homework Statement [/B] A spherical satellite of approximately uniform density with radius 5.1 m and mass 280 kg is originally moving with velocity 2600, 0, 0 m/s, and is originally rotating with an angular speed 2 rad/s, in the direction shown in the diagram. A small piece of space junk of...

I have the "robotic arm" shown in figure...the angular speeds w1, theta, w3 are given...they are asking me to find the total angular velocity of the disk. Can anyone explain me (conceptually) 1) what do we mean by total angular velocity of the disk and 2) how to find it...i have not understood...

Homework Statement For an eye in which the pupil has a radius of 3.0 mm, what is the smallest angular separation that can be resolved when two violet (λ = 400 nm) objects are placed side by side? Homework Equations theta_r = sin(theta_r) = 1.22(wavelength/d) The Attempt at a Solution theta_r...

Angular momentum is conserved in a closed system. Is thermal isolation required too? An example special case in mind is a closed cavity high speed rotation. It contains high pressure gas and the thermal flow is driving convection currents creating turbulence and or a heat pumping loop...

Hello! :) When solving a problem, I had to calculate the angular velocity of a homogenius rod when it comes to vertical position, after being released from a horisontal position (the rod is fixed at one end). This is as usually done with energy conservation, using the rotational energy of the...

Here is the problem I am working on. I have found answers for all of them except part (f), which is the one I need help with. I will report the answers I have so far: A classic 1957 Chevrolet Corvette of mass 1240 kg starts from rest and speeds up with a constant tangential acceleration of 2.00...

In an electron system (spin =1/2, l = 1) the total angular momentum will be J=S+L

Homework Statement Starting from rest, a spinning compact disk undergoes an angular acceleration of 5.0 rad/s^2. What is the angular speed of the disk after 3 revolutions? Homework Equations a=Δω/Δt ω=Δθ/Δt The Attempt at a Solution I do not understand how to solve this equation when I am not...

[Moderator's note: thread spun off from a previous one on a related but different topic.] Well that's another question that has been puzzling me for quite some time and would love to know the answer to it... Imagine 4 tubes of equal length, making a square, with 4 identical photons running...

Hey everyone, I just made an account because I have a problem concerning angular momentum and precession. In the picture below you see the vectors l1 and l2 that make up total orbital angular momentum L precess around L. I can get my head around why that is the case. The same for s1 and s2...

1. Homework Statement A door of width l = 1.00 m and mass M = 15.0 kg is attached to a door frame by two hinges. For this problem, you may ignore gravity, as we are interested in rotational motion around the vertical axis. There is no friction of any kind. An angry mother-in-law slams the...

Hello, I'm trying to figure out the free body diagrams for the inverted pendulum problem and I'm having trouble figuring out the one equation: ##Psin\theta + Ncos\theta - mgsin\theta = ml\ddot{\theta} + m\ddot{x}cos\theta## I've never really seen a mixed sum of forces equation before where some...

I know that the angular momentum of the moon with respect to the Earth can be calculated by L = Iw but if the L of the moon is k * Learth-sun the there will be way more eclipses, one of each every 28 days. So the momentum of the moon must change over time, how does it work?

Hi, I need any good books or articles about the mathematical analysis and modelling of orbital angular momentum Regards

Homework Statement Show that the quantization of angular momentum implies that the kinetic energy of the electron is quantized as K=nhforb/2, where forb is the frequency of rotation. Assume circular orbit. Homework Equations Radial acceleration: arad = v2/r = (4π2r/T = 2*π*v/Tr = nħ KE =...

I am doing an analysis concerning the torque-free motion of an axisymmetric body (J1 = J2 != J3). The angular velocity is given \omega(t) = [\omega_t\ sin(\Omega t), \omega_t\ cos(\Omega t), \omega_{z0}] where \omega_t, \Omega and \omega_{z0} are constants. I would like to determine the...

Homework Statement A girl places a rock in a sling and begins spinning it in a circular path above her head. By exerting a force on the sling, she increases the rock's speed while it goes around her head a few times, before releasing the rock. Options: 1. She exerts a force on the rock that is...

Homework Statement A star has an effective temperature T_{eff} and is observed to have a flux F. Show that the angular radius in arcseconds of the star (as seen from Earth) is given by \theta = (\frac{2.06 \times 10^5}{T_{eff}^2}) \sqrt{\frac{F}{\sigma}} Homework Equations L = 4 \pi R^2...

A sheet of metal in the shape of a triangle massing 10 kg per square meter is to be spun at an angular velocity of 4 radians per second about some axis perpendicular to the plane of the sheet. The triangle is a right triangle with both short sides of length 1 meter. (a) The axis of rotation is...

Hi everyone, I tried to find the Eigenstate of the angular momentum operator myself, more specifically I tried to find a Function Y_{lm}(\theta,\phi) with L_zY_{lm}=mħY_{lm} and L^2Y_{lm}=l(l+1)ħ^2Y_{lm} where L_z=-iħ\frac{\partial}{\partial \phi} and...

Homework Statement The rotating subunits forms an approximately cylindrical axel with a diameter of 4 nm and total mass of 80,000 Daltons. The motor takes three steps per revolution with each step taking 0.067 s. We can model the rotating subunits as a rotating cylinder and use the properties...

Homework Statement You hold a small ice cube near the top edge of a hemispherical bowl of radius 100 mm. You release the cube from rest. What is the magnitude of its acceleration at the instant it reaches the bottom of the bowl? Ignore friction. Homework Equations a=v^2/r delta U= delta Krot...

A rod of length L and mass M is rotating with angular velocity w about its center of mass. What is its angular momentum with respect to a rotating point 1/4L from the rod's end? What about a stationary point? Homework Equations With the respect to the center of mass, angular momentum L = Iw =...

Homework Statement A massless stick of length d, held parallel to the ground, has a mass, m, attached at one end of it and a pivot on the other end. A second mass, m, is glued on at a distance x from the pivot. At what distance x would maximize the angular acceleration of the stick the instant...

Hi, not a homework problem as such, but I am studying introductory quantum physics and having some trouble understanding how applying the rising or lowering operator for angular momentum implies: L+/-|l,m> ∝ |l, m+/-1> Basically, my question is the same as the first part (Q1) as described in...

On exactly what factors does the rotational angular velocity of a planet depend ? Can a mathematical expression be derived for it ?

Homework Statement Two discs of different radii and masses are kept on a smooth horizontal table and both are free to rotate about their fixed central vertical axis. One of them is given some angular velocity while other is stationary. The rims are brought in contact. There is friction between...

I'm trying to find out if this is angular momentum or something else. It says this, "If an object spins in a certain direction any pieces that break off that object must also spin in the same direction." Is that angular momentum or something else?

Homework Statement Gear r has angular acceleration of a magnitude of .2 rads^{-2}(counterclockwise) and is resting at t=0s . p is a cylinder welded to R (concentric). r applies torque to R, these do not slip or slide. A mass m hangs from a string which is attached to p. This string is not...

Homework Statement :[/B] Your car tire is rotating at 3.5 rev/s when suddenly you press down hard on the accelerator. After traveling 200 m, the tire’s rotation has increased to 6.0 rev/s. What was the tire’s angular acceleration? Give your answer in rad/s2. Homework Equations :[/B]...

Homework Statement Homework EquationsThe Attempt at a Solution If I interpret "magnitude of displacement of CM per sec " as Velocity of CM ,then Horizontal Impulse provided to the rod = J ##J = MV_{cm}## Angular impulse about the CM = JL/2 ##\frac{JL}{2} = I \omega ## ,where ##I =...

Hi, Some "derivations" of the law of the lever argue with conservation of energy: If one arm of the lever of length ##r_1## is pulled by a distance ##s_1## with force ##F_1##, the other arm moves by a distance ##s_2=s_1 \frac{r_2}{r_1}##. From conservation of energy ##E=F_1 s_1=F_2 s_2## it...

Homework Statement Given a reference frame O' moving at a constant speed $\vec{V}$ in relation to another reference frame O, I want to prove that ##\vec{r_{1B}} \times m_1\vec{v_{1B}} + \vec{r_{2B}} \times m_2\vec{v_{2B}} = \vec{r_{1F}} \times m_1\vec{v_{1F}} + \vec{r_{2F}} \times...

Homework Statement The problem deals with a charged (Q) rotating sphere around its axis (Ω_0) z^^ (z hat) of radius a. I'm asked to find the total angular momentum of the EM fields. 2. The attempt at a solution There is a solution posted to this question and I was just wondering why my...

Homework Statement A space station of mass 6.0 × 104-kg is to be constructed in the shape of a thin annular cylinder (or ring). The inner radius of the annular cylinder is 100-m, and the outer radius (and location of the floor) is 105-m. Artificial gravity equivalent to free-fall acceleration...

Homework Statement Hi all I am doing a school physics project and I am trying to find the maximum angular velocity of a DC motor. I have built a circuit consisting of a charged capacitor (of known voltage) and a motor. I then try to predict the maximum angular velocity attained by the motor...

Homework Statement Consider the following state constructed out of products of eigenstates of two individual angular momenta with ##j_1 = \frac{3}{2}## and ##j_2 = 1##: $$ \begin{equation*} \sqrt{\frac{3}{5}}|{\tiny\frac{3}{2}, -\frac{1}{2}}\rangle |{\tiny 1,-1}\rangle +...

Will the angular momentum of a half filled waterbottle increase? or decrease? or remain the same?

Homework Statement angular velocity about the axle = 65 rads^-1 diameter = 0.54m radius= 0.27m 1/2radius= 0.135m[/B]Homework Equations v=rw w=θ/t a=v^2/r=w^2r (Might be the probability that i have to use another equation)[/B]The Attempt at a Solution Firstly i cut the diameter in half which...

Say, I have two spin-1/2 particles in the states characterized by ##(n=2, l=1, m_l=1, m_s=1/2)##and##(n=2, l=1, m_l=1, m_s=-1/2)##. Now, using something like the jj coupling scheme, I first find out the (orbital+spin)angular momentum for the individual particles:(i) ##| 11\rangle...

Homework Statement The momentum carried by an electromagnetic field is [;\vec{P}(\vec{x}, t) = \frac{1}{4\pi c} \int d\vec{x}\vec{E}(\vec{x},t) \times \vec{B}(\vec{x},t);] show that for a finite field extension [;\vec{J}(\vec{x}, t) = \frac{1}{4\pi c}\int -i...

Two hollow spheres, both the mass and radius R M , which are rotating around a center of mass ( CM ) , with an initial period To, are kept distant from each other by an ideal wire with a distance of 8R. At a given instant a motor is driven by wrapping the wire and making the two spheres meet...

I think angular velocity can be measured in radians/second. I also heard that if I multiply a value of angular velocity that is in the units of Rad./sec. by a certain value of radius in meters, I will get m/s, but this is the instantaneous tangential velocity. Is any of these right? In...

Homework Statement a motor traveling at a constant speed is just able to completely go round a vertical circular track of radius 8m The total mass of motor is 210kg i)Compute the angular velocity at the top of the track ii)compute the maximum force on the track Homework EquationsThe Attempt...