Questions tagged [rotational-kinematics]
A tag for questions about rotational motion, including angular velocity and angular acceleration.
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How does physics deal with perpetual motion in spins?
This is a bit a bit of a weird question. Simply put, if a body such as a planet spins, there is no internal issue (that I know of) that would cause it to eventually stop (by internal I mean that an ...
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Why starts the rotation vector of a body in the intermediate axis theorem to rotate in the same direction as the body?
In this video, explaining the intermediate axis theorem (Dzhanibekov-effect) in a very nice way (around 7:52, from the perspective of the co-rotating frame where centrifugal are present) one can see (...
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Finding The Trajectory of particle Kept on a rotating surface
Suppose we "Keep" a particle on a circular, rotating turn-table, rotating with constant angular velocity $\dot{\theta}$, (i.e, the at $t=0$,when the particle makes contact with the table, the ...
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Can someone help me understand this equation that finds derivative of quaternion when angular velocity is known?
I found the following equation in an IEEE paper:
$\frac{dq}{dt} = \frac{1}{2}\text{Q}\omega$
where $q$ is the quaternion that rotates a vector from the body frame to the world, $q=\left[q(1), q(2), ...
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Stable Rotation Setup for Experiments (table version)
I am looking for a rotation devise like that one in this video below (from 00:40 seconds). Does anyone know where to get one, or have any idea about how to create a nice and stable rotation setup for ...
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Equation of Motion in Non-Planar Rotation
I'm trying to understand the equations of motion for a rigid body that is rotating and I am a bit stuck.
For a rigid body, assuming planar rotation (not necessary to be uniform), we can express the ...
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Angular Velocity of a point on a deflated tire (gyroscope measurement)
Before I do the experiment, I am a bit confused about the expected signals provided by a 3-axis gyroscope (angular velocities vs. time) mounted on the edge of a (slightly) deflated car tire when the ...
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Pure rolling on accelerated plank
A sphere at rest is placed on a plank. After that plank starts accelerating. My doubt is that what is the direction of motion of sphere when the plank starts accelerating to the right?
It is given ...
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Navier-Stokes equations for rotating falling object
I am considering the problem of a rigid body moving in a fluid, free to translate and rotate (say, for example, a falling body in a fluid).
Some of the approaches I found in some articles involve a ...
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How to find force needed to lift two wheels off ground during cornering?
I'm attempting to calculate the maximum velocity at which I can safely drive around a corner.
One scenario I'm considering is where all four wheels maintain contact with the ground, but slips. The ...
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How many illusionary axes of rotation can coexist?
Consider the answer to this question:
How many different axes of rotation can coexist?
Any rigid body, at any time, can only be rotating about one instantaneous axis of rotation.
Now, that ...
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Rotation of a disk - should there be a centripetal force?
See the diagram. The tension in the inextensible string should exert a torque causing a tangential acceleration on the rim of the disk. But should there always be a force towards the centre of the ...
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Rotation of Rigid body
How to prove the equation (4.14)
$$ a_{ij} a_{ik} = \delta_{jk} $$
from the equation (4.13)
$$ x_i' x_i' = x_i x_i $$
With summation convention I found it very easy.
But, using summation I am not ...
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What is centre of rotation and a ref. point fixed wrt to the body?
I'm studying Analytical Mechanics, and in the section about the kinematics of rigid body, it is mentioned the following concepts:
Center of rotation
a reference position that is fixed with ...
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Angular Momentum and assymetric axis
The question I came across ,
If a semicircular disc rotates uniformly (const. angular velocity) about an axis passing through its Centre of mass , and prependicular to its plane , do we need an ...
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