Angular Definition and 999 Threads

Homework Statement I don't understand, physically speaking, how do we get from the first equation to the second: how do we get the fact that velocity in body fixed frame equals to angular velocity in body fixed frame. Furthermore I dont' understand how we get the angular velocity in inertial...

Hey guys. I've seen this question asked on a few different forums, and I understand the basic gist of the answer but I am not yet satisfied with what I have read. People seem to have varying degrees of understanding of this, and I am the type of person that wants to understand things 100% and...

Homework Statement Ok I have the answers to parts a and b, which I am 100% confident in since they are simple computations Question is in attachement a)74.9 rad/s b)168.08 rad My issue comes in when I have to get parts c The mass of the cylinder is 8.7kg, its diameter is .18m, its .35m long...

https://en.wikipedia.org/wiki/Balancing_of_rotating_masses See the image in that page. I know intuitively why a direction of torque is counterclockwise-because of a centrifugal force. But an direction of angular momentum of that shaft with attached weights (ignore the shaft mass) is southeast...

Hello,in this link http://dtic.mil/dtic/tr/fulltext/u2/a028054.pdf a paper „Maximum Theoretical Angular Accuracy of Planer and Linear Arrays of Sensors“ can be found.The accuracies are given in equations 19 (respect to the x axis) and 20 (respect to the y axis).My question is: Shall the angle...

Angular momentum is the product of its moment of inertia and its angular velocity. So can we infer that since angular momentum is conserved then if an object has more moment of inertia then it will have lesser angular velocity and vice versa? Since from common sense we can make out that moment...

If a top has angular momentum of 12 units and the Earth has angular momentum of 100. Does this mean that Earth is spinning faster than the top since it has more angular momentum? The answer is there at the back of my head but can't articulate it.

350nm falls on a single slit of width of 0.20mm. What is the angular width of the central diffraction peak? I think that the width should be equal to 2Θ, where Θ=arcsin(m*λ/d)... m=1 and we have λ=350*10^-9 and d= 0.20*10^-6...but when i do the calculations I get 1.75 and the arcsin is a maths...

Do we find out angular momentum for an object from a specific position? Since L= r x mv. R is the distance from the centre of mass. So can I say that angular momentum is 12 for a fixed position 4 metres away from centre of mass having mass of 1 kg and velocity of 3 metres per second north?

Homework Statement Hi everybody! I would like to discuss with you a problem that I am wondering if I understand it correctly: Find expressions for the cartesian components and for the magnitude of the angular momentum of a particle in cylindrical coordinates ##(r,\varphi,z)##. Homework...

1. Homework Statement When the 3.2-kg bob is given a horizontal speed of 1.5 m/s, it begins to rotate around the horizontal circular path A. The force F on the cord is increased, the bob rises and then rotates around the horizontal circular path B. (picture included) Homework Equations L = I ω...

Homework Statement Small mass sits on a circular revolving table, 200 mm from center. It is given a constant angular acceleration of 2 rad/s. The static coefficient of friction is 0.2. At what angular velocity will the mass start to slip? Homework Equations ar=v2/r ar=r''-rθ'2 aθ=rθ''+2r'θ'...

For an equations such as this what goes into the θ? θ = sinθ or θ = θ? Let's say if the angle of displacement = 45° do I just plug 45° as θ into the equation below or should it be sin(45°)? Or is it θ = S/R ? ωf2 = ωi2 + 2 α (θf - θi)

I am having trouble visualizing which two tires of a car will be pushed down based on the angular momentum and torque of that car. Let's say if its angular momentum is point OUT while its torque is pointing UP in relations to the picture below. My guess is it's the two right wheels of the...

Homework Statement The absolute angle of the thigh has the following angular velocities during the support phase of walking. Calculate the angular acceleration at time 0.02s in rad/s and in deg/s Time (s) Angular Velocity (rad/s) 0 s ----...

during knee flexion of a squat phase the knee moves from 180 degrees to 95 degrees. if you perform 10 complete squats what is the total angular distance (in radians and in degrees), undergone at the knee? anyone know how to solve this one? can you explain

I need some clarification on a homework problem related to angular momentum. I understand how to calculate the angular momentum by using L= IW but when calculating the moment of intertia for the particle i don't understand why to use .5m as the radius instead of .4m due to being placed at the...

So I'm doing an experiment where I am using five different methods to find the spring constant of a spring. These three values of k should be the same but alas, they are not :( and I am at a loss as to why. The first method was by using hooke's law and finding the displacement and graphing the...

Homework Statement A large wooden turntable in the shape of a flat disk has a radius of 1.50 m and a total mass of 100 kg. The turntable is initially rotating about its vertical axis through its centre with an angular velocity of 2.50 rad/s. From a very small height a 100 kg sand bag is...

Homework Statement [/B] A mass of 6.1 kg tied to a string is wrapped around a disk as shown. If the disk has a mass of 8.2 kg and a radius of 2.3 m, how fast will the disk be rotating when the weight has fallen 7.4 m and was released from rest? Homework Equations Θ = S/R = x/R Θ = 0.5 α t^2 τ...

Homework Statement A Person sitting firmly over a rotating stool has his arms stretched. If he fold his arms, his angular momentum about the axis of rotation : A.) Increases B.) Decreases C.) Remains Unchanged D.) doubles Homework Equations [/B]Conservation of Angular Momentum The...

Homework Statement I need to find a way to do a conversion between the angular motion of a motor to the angular motion of an oscilating bar that is connected to it through a sliding and rotating collar. This way, every time the motor completes a revolution, the bar swings back and forth with a...

Homework Statement An object is in uniform circular horizontal motion at the end of a chord of length L. Its tangential speed is v. The chord is pulled into length 0.5L in such a way that the tension in the chord remains constant. As a result, the tangential speed: a) remains constant b)...

Homework Statement A satellite is in a circular orbit of radius R from the planet's center of mass around a planet of mass M. The angular momentum of the satellite in its orbit is: I. directly proportional to R. II. directly proportional to the square root of R III. directly proportional to...

So the moment of inertia or a ring is MR2 I don't understand why. Here is my reasoning Consider this shape (the ball is a point), the moment of inertia is MR2, there I agree but now what happens when you add another point on the other side since I = ΣMR2 then this is 2MR2 What about a...

Homework Statement A ball rolls down an incline plane without slipping. What is the ratio of its angular velocity at h/3 to its angular velocity at 2h/3? 1) 1:2 2) 1:sqrt(2) 3) 1:1 4) sqrt(2):1 5) 2:1 Homework Equations Conservation of energy with provisions for rotational and...

Homework Statement Two cars collide head on but offset from each others center of gravity. After the impact the two cars are locked together as one body. Due to the location of the collision point, the impact causes the two locked cars to spin clockwise. Car A- traveling west going 10 mph...

I'm looking through an old exam, and don't quite understand the solution given for one of the problems. We have given a wavefunction g(\phi,\theta) = \sqrt{\frac{3}{8\pi}}(-cos(\theta) + isin(\theta)sin(\phi)) and are asked what possible measurements can be made of the z-component of the...

Homework Statement This is not really a question on how to solve the problem, I'm just trying to get clarification on something. For angular acceleration, α, can someone explain to me what αz is? And why does αz = α / R = αy? I understand the rest of the problem, I just don't understand...

Consider addition of two angular momenta J = J1 + J2 , with j1=j2=1. Find the eigenstates of the total angular momentum I jm > in terms of the product states I j1 m1 j2 m2 > in two ways (a) Make use of the tables of the Clebech _Gordan coefficients (b) The state with m1 = m2 = 1 must be a...

Homework Statement A 30 kg wheel has a center of mass 0.1 m left from the center of the wheel and radius of gyration KG = 0.15 m. Find the angular acceleration if the wheel is originally at rest. The radius of the wheel is 0.25m. Homework Equations I=mk^2 T=f*d M=I*a Fn acting bottom in Y...

Homework Statement A thin rod of length l and mass M rotates about a vertical axis through its center with angular velocity ω. The rod makes an angle φ with the rotation axis. Determine the magnitude and direction of L (angular momentum). So we're given: mass - M, length - l, angular velocity...

Hello, See attached PDF for basic depiction of an issue I am currently working on. If lid starts off with angle = 0 (closed) and I fling it open until it hits the "stop" (interferes with bottom causing it to stop), how fast must lid being traveling to tip over entire assembly? From this I want...

Homework Statement http://pho.to/A7jM2 Homework EquationsThe Attempt at a Solution My question is why the answer of question 15.258 (a) about the angular acceleration of rod BD isn't correct. I used the realtion of tan(25) in the end of the solution.

If one can't ever know all the three components of (QM) angular momentum, then can it even be considered as a "vector"? Is it only cause it transforms as a vector in a coordinate transformation?

Homework Statement A projectile of mass m is launched with an initial velocity [PLAIN]https://www.webassign.net/images/boldv.gifi making an angle θ with the horizontal as shown below. The projectile moves in the gravitational field of the Earth. Find the angular momentum of the projectile...

I'm confused about situations involving rotating frames in which the angular momentum is conserved and the initial velocity does not change. I'll make an example. Take a rotating carousel (constant angular velocity) with no friction on it and a ball. At the initial time instant the ball has the...

Homework Statement Homework Equations θ =1.22λ/d The Attempt at a Solution for (a) θ =1.22λ/d θ =1.22(579nm)/(1.2cm)[/B] θ =5.8865x10^-5 degree= 1.027x10^-6 rad but the answer =2x10^-3rad , for the micorscope, the formula of angular resolution is different? i...

Homework Statement A uniform, 4.5-kg, square, solid wooden gate 1.5 m on each side hangs vertically from a frictionless pivot at the center of its upper edge. A 1.1-kg raven flying horizontally at 5.0m/s flies into this door at its center and bounces back at 2.0m/s in the opposite direction...

Homework Statement a small 0.199 kg block slides down a frictionless surface through height h = 0.608 m and then sticks to a uniform vertical rod of mass M = 0.398 kg and length d = 2.23 m. The rod pivots about point O through angle θ before momentarily stopping. Find θ. point O is at the end...

Homework Statement In the figure, a small 0.235 kg block slides down a frictionless surface through height h = 0.471 m and then sticks to a uniform vertical rod of mass M = 0.470 kg and length d = 2.36 m. The rod pivots about point Othrough angle θ before momentarily stopping. Find θ. Homework...

Homework Statement If a bike wheel rotates 9.4 times while slowing down to a stop from an initial angular velocity of 8.1 rad/s, what is the magnitude of the angular acceleration in rad/s/s Homework Equations α = at / r α = ω / t α = Θ / t^2 ω = Θ / t ω = v / r Θ = ω t + 0.5 α t^2 v final = v...

Homework Statement A.) For the graph above what is the angular displacement during the 4 seconds of motion? B.) For the graph above what is the angular acceleration from t=2 to t=4? Homework Equations α = at / r α = ω / t α = Θ / t^2 ω = Θ / t ω = v / r Θ = ω t + 0.5 α t^2 The Attempt at a...

Homework Statement A car is traveling at 27.8 m/s, it undergoes a negative acceleration of 2.6 m/s/s when the brakes are applied. How many revolutions will the tires go through before the car comes to a stop if the wheels each have a radius of 1.0 m? Homework Equations α = at / r...

Torque ##\tau## should be in the same direction as the change in angular momentum ##\Delta L##, but the following example seems to suggest otherwise. Consider a cone rolling on its side without slipping on a flat surface. Let the apex be the origin and the initial coordinate of the center of...

Homework Statement Homework Equations Langevin equation (I included all the equations in the next section.[/B]The Attempt at a Solution I do not know how I can proceed from this point. I'm stuck since I have no information on the drag coefficient. Maybe my approach is wrong, and there may...

I'm trying to understand the relations between the existence of Coriolis force and the conservation of angular momentum. I found this explanation on Morin. I do not understand the two highlighted parts. In particular it seems that Coriolis force is there to change the angular momentum of the...

Consider a tiny planet orbiting a massive star. If the value of the planet's angular momentum (w.r.t. to star) is fixed, does the action of the planet's orbit depend on the eccentricity of the orbit?

For the rotation of a rigid body about a fixed axis z the following holds. $$\vec{\tau_z}=\frac{d\vec{L_z}}{dt}= I_z \vec{\alpha} \tag{1}$$ Where \vec{\tau_z} is the component parallel to the axis z of a torque \vec{\tau} exerted in the body; \vec{L_z} is the component parallel to the rotation...

I do not get some points of this proof about the time derivative of a unit vector $\hat{u}$ (costant magnitude) which is following a precession motion. The picture is the following. I want to prove that $$\frac{d\hat{u}}{dt}=\vec{\Omega}\wedge \hat{u}.$$ I'm ok with almost all the proof except...