Linked Questions
23 questions linked to/from Understanding terms Twist and Wrench
21
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13
answers
11k
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Why is force a vector?
"We have focused our discussion on one-dimensional motion. It is natural
to assume that for three-dimensional motion, force, like acceleration,
behaves like a vector."- (Introduction to Mechanics) ...
21
votes
10
answers
6k
views
Why is velocity a vector?
Velocity has a magnitude and a direction and thus it is considered a vector.
But from linear algebra perspective, a vector is an element of a vector space.
A set of mathematical objects can be a ...
2
votes
9
answers
825
views
Is Conservation of Linear Momentum subservient to conservation of Angular Momentum?
When particles physically interact, they transfer linear momentum and angular momentum between one another via force .
When particle P1 exerts force on particle P2, P2 exerts an equal and vectorially ...
2
votes
3
answers
5k
views
Moment of a force about a given axis (Torque) - Scalar or vectorial?
I am studying Statics and saw that:
The moment of a force about a given axis (or Torque) is defined by the equation:
$M_X = (\vec r \times \vec F) \cdot \vec x \ \ \ $ (or $\ \tau_x = (\vec r \times ...
4
votes
5
answers
1k
views
Forces as vectors in Newtonian mechanics
I seem to be confused about the nature of forces as vectors, in the basic Newtonian mechanics framework.
I know what a vector is as a mathematical object, an element of $R^3$. I understand that if a ...
1
vote
3
answers
5k
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Why can you add moment vectors?
My book says the following:
If the body is acted upon by a system of forces, the resultant moment of the forces about point O can be determined by vector addition of the moment of each force. The ...
4
votes
2
answers
2k
views
Angular Momentum of a rigid, extended object: When we see a rotating object, is the state of rotation totally relative?
Angular momentum of an object is a physical quantity that depends on the chosen point about which to calculate the angular momentum.
It is often said that an object that has been thrown up in the air ...
6
votes
2
answers
506
views
Is Velocity Really a Vector?
In non-relativistic physics, physical quantities $Q$ are characterized by how they transform under a Galilean transformation $g \in \mathcal{G}$.
$$ Q \rightarrow Q' = D[g]Q$$
where $D[g]$ is the ...
1
vote
2
answers
1k
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Does a body always rotate purely about its center of mass? [duplicate]
For example : A rod is held stationary in vertical position on a smooth horizontal ground and then released. Now the center of mass has velocity and acceleration and every point of the rod has some ...
2
votes
2
answers
1k
views
What are the mathematical models for force, acceleration and velocity?
In mechanics, the space can be described as a Riemann manifold. Forces, then, can be defined as vector fields of this manifold. Accelerations are linear functions of forces, so they are covector ...
1
vote
1
answer
1k
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How is the "wrench" a simplification for a general force-couple system? [closed]
from engineering mechanics, by beer and johnston
For any system of n forces, we can simplify this system to a Force-Couple system. The simplification is intuitive- we don't need lot of forces just a ...
6
votes
3
answers
486
views
Modelling an inelastic, rough, constrained collision
Understood situations:
a) Inelastic, rough collision of free spheres
In such a collision, two coefficients are used. The coefficient of restitution in the normal direction (the ratio $c_N$ of relative ...
5
votes
3
answers
221
views
Why can the "arrow" vectors be slid parallelly anywhere in space?
So, I was studying for my first E&M course from Griffiths and the first chapter is mostly math preliminaries. Griffiths has a section starting page 10 on "How Vectors Transform?" where ...
1
vote
2
answers
698
views
Angular momentum of a body about a point rotating about its own axes
I want to calculate angular momentum of a sphere about point O. The sphere is rotating about its two axes with angular velocities $w_1$ and $w_2$.
I know that angular momentum = $m\vec{r}\times\vec{v}...
1
vote
1
answer
773
views
Rigid body rotation and translation about an arbitrary axis
If you have a disk which is rotating on a surface without slipping then we can view the motion in two different ways. Firstly as a rotation about the centre of mass of the disk along with a ...