The angular-velocity tag has no wiki summary.
1
vote
1answer
29 views
Determine the velocity and acceleration of the vertex $B$
1) The bent rod $ABCD$ rotates about the line $AD$ whit a constant angular velocity of $90 rad / s$. Determine the velocity and acceleration of the vertex $B$ when the rod is in the position shown in ...
1
vote
0answers
44 views
Closed-form equation for orientation and angular velocity over time
If a rigid body, rotating freely in 3d, experiences no friction or other external forces and has an initially diagonal inertia matrix $\mathbf{I}_0$ (with $I_{11}>I_{22}>I_{33}>0$) and ...
0
votes
1answer
70 views
Circular motion and centrifugal force
Assuming a race car drives around in a circle of radius r, center (0,0), linear velocity v, and ignoring centrifugal forces and friction I can calculate the position at any time, t.
Angular velocity
...
2
votes
0answers
37 views
How to get from angular velocity to acquired phase for neutrino oscillations in matter?
I am reading Akhmedovs 2000 paper on parametric resonance, and I cannot figure out the math of this particular passage:
The difference of the neutrino eigenenergies in a matter of density $N_i$ is ...
5
votes
1answer
163 views
Drag on a spinning ball in fluid
I am a physics newbie (high school level) and I am wondering what happens when a spherical object is spinning on the spot in a bunch of gas (no gravity here, just an imaginary physics sandbox).
Am I ...
0
votes
2answers
140 views
Lagrange-Euler equations for a bead moving on a ring
A bead with mass $m$ is free to glide on a ring that rotates about an axis with constant angular velocity. Form the Lagrange-Euler equations for the movement of the bead.
Solution: Let us ...
1
vote
0answers
38 views
Truck driven from a small motor that can carry a heavy load, yet can travel fast.
I am building a truck from trash as materials. I have one small motor and a a few small gears, but no other engineered materials are allowed. The truck must carry a load for a distance of 3m. The ...
0
votes
1answer
172 views
Does weight distribution affect angular velocity?
If an equal torque of equal radius and size is produced on two bodies of the same weight and same center of gravity, but with different weight distribution (say one has a 1kg mass 1 meter above the ...
10
votes
1answer
180 views
What are the consequences of relativistic angular velocities?
If I take a rod of some radius $r$ and length $L$, and I spin this rod with angular velocity $\omega$. How would the geometry of the rod appear to an observer as one converges to $c$? What are the ...
0
votes
0answers
65 views
Units and use of the formula of the angular acceleration? [closed]
Question: On my document, it is written:
Angular acceleration:
$$ \frac{d\omega}{dt}=r\times \alpha $$
What are the units please?
What are $d \omega$, $dt$ and $r$?
I already know that $\alpha$ is ...
0
votes
0answers
235 views
How to find angular velocity of a point inner a circumference
Let's consider a cicumference that have the center in the origin of axes and rotates around x-axes. Let's stick a bar in a point $A$ of this circumference and at the end of the bar let's stick a mass ...
1
vote
0answers
241 views
Rotational Dynamics Problem-Rod slipping against block
A uniform rod of mass m and length l is pivoted at point O. The rod is initially in vertical position and touching a block of mass M which is at rest on a horizontal surface. The rod is given a slight ...
1
vote
1answer
102 views
Appearing To Reverse Object's Rotation
Can it be done, and if so, how does one you explain mathematically the ability to cause a rotating object to appear to change the direction of rotation? I believe it has something to do with angular ...
3
votes
2answers
942 views
Does Earth's Rotation Affect Its Shape?
The question I am working on is, "Consider the following.
(a) Find the angular speed of Earth's rotation about its axis. rad/s
(b) How does this rotation affect the shape of Earth?"
I am fully ...
0
votes
2answers
260 views
Vector Nature Of Angular Velocity
I am currently reading about angular position, angular velocity, and angular acceleration. I came across this paragraph that was particularly confusing, and was wondering if someone could perhaps help ...
1
vote
2answers
376 views
Applying angular velocity to a rotation matrix
I have a very simple question. In our project we store an object's orientation as a 3x3 matrix which holds the orthonormal base of that object's local space. For instance if the object is aligned with ...
0
votes
3answers
2k views
Finding Angular Acceleration of rod given radius and angle
A uniform rod is 2.0 m long. The rod is pivoted about a horizontal, frictionless pin through one end. The rod is released from rest at an angle of 30° above the horizontal. What is the angular ...
2
votes
1answer
158 views
Finding Max Radius of Propeller (angular velocity)
I am looking at a question from University Physics
The given answer
Whats the intuition behind using the below diagram
of finding $v_{tip}$? I was looking the the $v_{tan}$ not knowing how ...
1
vote
1answer
81 views
Time for a wind-battred door to slam
Foolishly leaving the window too widely open, earlier today my bathroom door slammed shut with the wind. How could I theoretically work out the time it takes to close?
Would it be impossible to ...
2
votes
1answer
206 views
what happens when I roll a gyroscope along its axis of spin
Say:
I have a gyroscope that is spinning in the xy plane along the z axis.
I then roll its spinning axis by some angle theta
Now I know the gyroscope will resist my attempting to change its axis ...
1
vote
3answers
530 views
Time period of torsion oscillation
The time period for a wave of frequency $\nu$ is given by $T = \frac{1}{\nu}$ or in other words, $T=\frac{2\pi}{\omega}$ where $\omega$ is the angular velocity...
For the oscillation of a torsion ...
1
vote
2answers
298 views
motion in the body-fixed frame?
This is really basic, I'm sure: For rigid body motion, Euler's equations refer to $L_i$ and $\omega_i$ as measured in the fixed-body frame. But that frame is just that: fixed in the body. So how ...
2
votes
2answers
456 views
Meaning of angular velocity in a rotating system
When you study the motion of a rigid body you have $\vec\omega$, the vector associated to angular velocity. In the case you are using Euler angles and want a quick formula for the rotational kinetic ...
1
vote
1answer
276 views
Cases in which angular velocity and angular momentum point into same direction
I know that angular momentum $\vec{L}$ and angular velocity $\vec{\omega}$ of a rigid body doesn't point into the same direction in general. However if your body spins around a principal axis, ...
2
votes
3answers
1k views
Angular momentum equations
I do not understand this because angular momentum is $L=I\omega$ ($I$ is moment of inertia;$\omega$ is angular velocity) but it I have also seen equations where $L= rmv\sin(x)$. I do not understand ...
1
vote
1answer
222 views
What conditions must be met for a ball to roll perfectly down an incline without slipping?
What conditions must be met for a ball to roll perfectly down an incline without slipping? A mathematically rigorous definition, please.
I honestly don't know where to begin with answering this ...
-1
votes
1answer
313 views
How to get angular acceleration from spin count and angular velocity [closed]
It would be very good if someone explained me how do you get to the final answer which is already know (3.2 rad/s^2)
Have been given:
ω = 20 = angular velocity (rad/s)
N = 10 full spins
Need to find:
...
0
votes
1answer
178 views
Angular velocity $\omega$ by $v$
We have two girls, with mass (M). They become close to each other in speed of V. The distance between them is 3L.
I was asked to calclute the Angular velocity (w) of the two girls. So I set the ...
1
vote
2answers
500 views
What are the expressions for rotational and translational kinetic energies of a system of point particles?
Consider a system of point particles , where the mass of particle $i$ is $\mu_i$ and its position vector is $r_i$. What are the expressions for translational kinetic energy and rotational kinetic ...
2
votes
1answer
1k views
Merry go round physics problem?
So I have the following statement.
"A merry-go-round is spinning with a fixed angular speed. As a person is walking towards the edge, the force of static friction must increase in order for the ...
0
votes
2answers
287 views
Finding work done by rotational force?
A disk with a rotational inertia of 5.0 kg·m2 and a radius of 0.25 m
rotates on a fixed axis perpendicular to the disk and through its
center. A force of 2.0 N is applied tangentially to the ...
1
vote
1answer
162 views
Finding stopping time when only given initial angular velocity and an expression for angular acceleration?
Question:
A wheel starts is spinning at $27\text{ rad/s}$ but is slowing with an angular
acceleration that has a magnitude given by $\alpha(t) = (3.0\;\mathrm{rad/s^4})t^2$. It stops in a time ...
0
votes
1answer
530 views
Simple Harmonic Motion Question [closed]
I have two formulae:
Displacement = Amplitude * Cos(Angular Frequency * Time)
Velocity = - Amplitude * Angular Frequency * Sin(Angular Frequency * Time)
OR
$x = Acos(wt)$
$v = -A.w.sin(wt)$
And ...
3
votes
1answer
312 views
Equation that tells me the rpm and mass of a spinning disk needed to keep a second large mass stable using gyroscopic effects
I am trying to figure out how large of a mass and how quickly I need to spin said mass to keep a two-wheeled robot stable. Ideally, I am looking for a formula that relates m1=mass of robot, m2=mass of ...
2
votes
3answers
21k views
Linear acceleration vs angular acceleration equation
I'm learning about angular velocity, momentum, etc. and how all the equations are parallel to linear equations such as velocity or momentum. However, I'm having trouble comparing angular acceleration ...
1
vote
2answers
3k views
What is the difference between angular speed and tangential speed in a circular motion?
I was looking a long time for the way the equations of this two speeds are obtained, and i found pretty much nothing important, so can someone explain how are those obtained, and which is the ...
0
votes
1answer
1k views
Tennis serving machine— How does a spinning ball bounce?
I have an idea of making a tennis serving machine. I will briefly describe what it is:
The machine is configured to serve the ball at a fixed speed to the center of the left (or right) service court
...
11
votes
1answer
1k views
Home experiments to measure the RPM of a pedestal fan without special equipment?
Is it possible to determine to an approximate degree, the revolutions per minute of a fan, for example a pedesal fan pictured below, without using some electronic/mechanical measuring device?
One ...
3
votes
2answers
770 views
Dynamics of moment of inertia
I'd like to be able to determine the angular acceleration of a system of two rotating masses, which are connected so as to have a variable mechanical advantage between the two. My background with ...
1
vote
1answer
2k views
Calculation of the G-force
I have a formula which is $\text{G-force} = \frac{v\omega}{9.8}$, where $v$ is speed and $\omega$ is the angular velocity. I've seen on the internet that G-force is actually $\text{acceleration}/9.8$. ...
6
votes
3answers
840 views
How is it that angular velocities are vectors, while rotations aren't?
Does anyone have an intuitive explanation of why this is the case?
