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[NOTES/CM-08009] Centrifugal force --- Effect of Earth's Rotation

Node id: 6222page

The effect of Coriolis force on the force acting on a body on the earth is computed at the poles, equator and at a general point. he banking of railway tracks and of roads is briefly discussed.

kapoor's picture 24-06-19 16:06:55 n

[NOTES/CM-08015] Rotations in Three Dimensions

Node id: 6301page

The set of all rotations that can be implemented physically  in three dimensions form a group. These most important and frequently used rotations are the rotations which can be implemented physically. These rotations, do not change the handedness of the coordinate axes and are called proper rotations. The improper  rotations take left handed systems to right handed systems, or vice  versa. The statement of  Euler's theorem about rotations is given.

kapoor's picture 24-06-18 05:06:55 n

[NOTES/CM-08013] Rotation of a Vector about \(X_3\)- Axis

Node id: 6230page

We derive the transformation rules for a rotation about \(X_3\)- axis.  The concept of active and passive rotations is briefly explained.

kapoor's picture 24-06-17 22:06:43 n

[NOTES/CM-08011] Rotations about a fixed axis

Node id: 6224page

Rotations about a fixed axis form a one parameter subgroup of  rotations.

kapoor's picture 24-06-17 22:06:47 n

[NOTES/CM-08006] Axis Angle Parametrization of Rotation Matrix

Node id: 6218page

A closed form expression for rotation matrix is derived for rotations about an axis by a specified angle \(\theta\).

\begin{equation}
R_{\hat{n}}(\theta)=\widehat {Id}-\sin (\theta) (\hat{n}\cdot \vec{I})+(1-\cos \theta)(\hat{n}\cdot\vec{I})^{2}
\end{equation}Here  \(\widehat{Id} \) is the identity matrix. and \(\vec{I}=(I_1,I_2,I_3)\) is given by 
\begin{equation} I_1=\left[\begin{array}{clc} 0 &0 &0\\ 0 &0 &-1\\ 0 &1 &0 \end{array}\right],I_2=\left[\begin{array}{clc} 0 &0 &1\\ 0 &0 &0\\ -1 &0 &0 \end{array}\right],I_3=\left[\begin{array}{clc} 0 &-1 &0\\ 1 &0 &-1\\ 0 &1 &0 \end{array}\right] \end{equation}. 

Also the components of the position vector a point transform a

\begin{equation} {\vec{x}}\Prime=(\hat{n}\cdot{\vec{x}})\hat{n}+\cos\theta\big(\vec{x}-(\vec{x}\cdot\vec{n})\hat{n}\big)-\sin\theta (\hat{n}\times \vec{x})\end{equation}

 

kapoor's picture 24-06-17 22:06:34 n

[NOTES/CM-08004] Equation of Motion in Non Inertial Frames

Node id: 6220page

 We derive an expression for Lagrangian for motion of a charged particle in a rotating frame, It is shown that the equation of motion can be written as

\begin{eqnarray} m\ddot{\vec{x}}=\vec{F_{e}}-2m\vec{\omega}\times{\dot{\vec{x}}}-m\vec{\omega} \times(\vec{\omega}\times\vec{x}) \end{eqnarray} where \(\vec {F}_e\) is the external force. As seen from the rotating frame, the particle moves as if it is under additional forces

  • $-2m\vec{\omega}\times{\dot{\vec{x}}}$ is called Coriolis force
  • $-m\vec{\omega}\times(\vec{\omega}\times\vec{x})$ is known as centrifugal force 

 

kapoor's picture 24-06-17 20:06:56 n

[NOTES/CM-08014] Active and Passive Rotations

Node id: 6229page

The active and passive view of rotations are defined and relationship between them is described.

 

kapoor's picture 24-06-17 19:06:18 n

[NOTES/CM-08001] The Group of Special Orthogonal Matrices in \(N\) Dimensions

Node id: 6232page

All  orthogonal  all \(N\times N\) orthogonal matrices  form a group called \(O(N)\). The set of all orthogonal  matrices with unit determinant  form a subgroup \(SO(N)\) . The group of all proper rotations coincides with \(SO(3)\).

kapoor's picture 24-06-16 15:06:35 n

[NOTES/CM-08010] Motion in Frames with Linear Acceleration

Node id: 6223page

The equations of motion in a linearly accelerated are are derived and an expression for pseudo force is obtained.

kapoor's picture 24-05-09 12:05:47 n

[NOTES/CM-08003] Euler Angles

Node id: 6216page

Euler angles are an important ways of parametrization of rotations. The definition of Euler angles and  and expression of  the rotation matrix in terms of the Euler angles are given.

kapoor's picture 24-05-09 12:05:39 n

[NOTES/CM-08008] Proper Rotations and $SO(3)$

Node id: 6219page

The definition and properties of proper rotations are presented.

kapoor's picture 24-05-09 10:05:41 n

[NOTES/CM-08012] Matrices for Rotations about Coordinate Axes

Node id: 6225page

The rotation matrices for rotations about the three axes are listed.

kapoor's picture 24-05-03 08:05:13 n

[NOTES/CM-08002] An explicit form of rotation matrix

Node id: 6214page

For two sets of coordinate axe \(K\) and \(K^\prime\) having common origin, an explicit form of the rotation matrix connecting them is obtained in terms of direction cosines.

kapoor's picture 24-05-03 04:05:37 n

[NOTES/CM-08005] Finite Rotations of Vectors about an Arbitrary Axis

Node id: 6217page

Using geometrical arguments, we will derive the result \begin{equation}\vec{A}^\prime = \vec{A} - (\hat{n}\times\vec{A})\, \sin\alpha + \hat{n}\times (\hat{n}\times\vec{A})\, (1-\cos\alpha ) \end{equation}between components of vectors related by a rotation by and angle \(\theta\) about an axis \(\hat n\).

kapoor's picture 24-05-02 20:05:20 n
 
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