Name: mars spin under no torque
Uploaded: 2024-03-07T13:22:29.000Z
Duration: 1 min 15 s
Channel: JoVE

El movimiento sin par se refiere al movimiento de un cuerpo rígido sin que ningún par externo actúe sobre él.
Considere un objeto axisimétrico, donde el eje z es el eje de simetría, con el centro de masa definido en el origen del marco de referencia giratorio. Aquí, el momento de inercia alrededor de los ejes x e y es igual.
Considere el sistema de referencia inercial definido de tal manera que el eje Z positivo del marco inercial está a lo largo del vector momento angular y forma un ángulo θ con el eje z positivo del marco giratorio.
Por lo tanto, el momento angular se puede expresar en términos de vectores unitarios de dos maneras, y al igualar los componentes de los vectores unitarios, se deriva la ecuación para la velocidad angular del objeto.
Además, escribiendo la velocidad angular en términos de desplazamiento angular e igualando los componentes nuevamente se obtiene la ecuación de movimiento para un cuerpo rígido axisimétrico sin torque.
Aquí, el momento angular, la precesión y el espín del objeto permanecen constantes durante todo el movimiento junto con el ángulo θ.

movimiento libre de torsión

Torque Free Motion

El movimiento sin torque se refiere al movimiento de un cuerpo rígido en el espacio cuando no actúan pares externos sobre él. Este tipo de movimiento se puede observar en entornos donde no hay fuerzas ni fricciones externas, como en el espacio exterior. Por ejemplo, la rotación de Marte en el espacio es un movimiento sin torsión. Marte es un objeto axisimétrico, lo que significa que tiene un eje de simetría a lo largo del cual gira, denominado eje z. El sistema de referencia giratorio se define de manera que el centro de masa de Marte esté en el origen. Esta disposición asegura que los momentos de inercia alrededor de los ejes x e y sean iguales.

Se utiliza un marco de referencia inerte adicional para analizar más a fondo el movimiento de Marte. En este marco inerte, el eje Z positivo se alinea con el vector de momento angular de Marte. Forma un ángulo theta (θ), con el eje z positivo del marco giratorio. El momento angular de Marte se puede expresar de dos formas diferentes utilizando vectores unitarios. Al equiparar los componentes de estos vectores unitarios, se puede derivar una ecuación para la velocidad angular del objeto. Además, al expresar la velocidad angular en términos de desplazamiento angular y equiparar los componentes una vez más, se llega a la ecuación de movimiento de nuestro objeto rígido, axisimétrico y sin torsión que vive en Marte.

Durante todo el movimiento de Marte, su momento angular, precesión, giro y ángulo θ permanecen constantes. Estas constantes revelan la intrigante dinámica del movimiento sin torsión en Marte.

Movimiento libre de torsión

El movimiento sin par se refiere al movimiento de un cuerpo rígido sin que ningún par externo actúe sobre él.
Considere un objeto axisimétrico, con el eje z ...

Education

Educación

JoVE Core

Mechanical Engineering

Ingeniería Mecánica

Unit 1

Unidad 1

3-Dimensional Kinetics of a Rigid Body

Cinética tridimensional de un cuerpo rígido

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

mars spin under no torque

Torque-free motion describes the movement of a rigid body when no external torques act on it. It can be seen in places with no outside forces or friction, such as outer space. Mars is one example of this kind of motion because it rotates in space without external torque.

Mars is an axisymmetric object, which means it has an axis of symmetry. That symmetry defines the rotating z-axis. The rotating frame is set so that Mars&amp;#39;s center of mass is at the origin. This setup makes the moments of inertia about the x and y axes equal.

The motion is also studied in a separate inertial frame of reference. In that frame, the positive Z-axis points along Mars&amp;#39;s angular momentum vector. The Z-axis forms an angle theta (&amp;#952;) with the positive z-axis of the rotating frame. Mars&amp;#39;s angular momentum can then be written in two different ways using unit vectors.

By matching the components of those unit-vector forms, the angular velocity of the object can be found. The angular velocity can also be written in terms of angular displacement. When those components are matched again, the equation of motion for the torque-free, axisymmetric rigid object is obtained. During the motion, Mars&amp;#39;s angular momentum, precession, spin, and the angle theta remain constant.

Mars Spin Under No Torque

moments and product of inertia

Moment and Product of Inertia Basics

Moment of inertia and product of inertia describe how mass is distributed in a rigid body. They help show how the body responds about coordinate axes and planes. For a small mass element, the moment of inertia is found by multiplying the element's mass by the square of the shortest distance to one of the three coordinate axes. That same idea is extended to the whole body by integration. Adding the contributions of all the small mass elements gives the body's moment of inertia about that axis.

inertia tensor

Principal Axes and Moments of Inertia

The inertia tensor describes how mass is spread out in a rigid body and how that body resists rotation. It is written as a 3×3 matrix, and each entry represents a moment of inertia about a particular axis. This makes the tensor a compact way to study rotational behavior in three dimensions. The diagonal entries show the moments of inertia about the principal axes. These principal axes are the directions where the object has the least resistance to rotation. A smaller moment of inertia along...

moment of inertia about an arbitrary axis

moment-of-inertia-about-an-arbitrary-axis

Calculating Moment of Inertia on Any Axis

Moment of inertia can be calculated about any chosen axis, not just a principal axis. It depends on the mass distribution of the object along that axis. This makes it useful when an object rotates in a real machine or other setup where balance and stability matter. To find the moment of inertia about an arbitrary axis, the perpendicular distance from the axis to each mass element is needed. That distance is obtained with a cross product between the unit vector that gives the axis direction and...

angular momentum about an arbitrary axis

Angular Momentum Relative to Point P

Angular momentum relative to point P is found by adding the motion of every mass element in a rigid body. The body has mass m and a center of mass at point G. It rotates in an inertial reference frame, and the angular momentum at P comes from the cross product of each position vector and its linear momentum. To build the full expression, the velocity of each mass element is written as two parts. One part is the translational velocity of the body. The other part is the relative velocity caused...

angular momentum and principle axes of inertia

angular-momentum-and-principle-axes-of-inertia

Angular Momentum in Principal Axes

Angular momentum in a rigid body can be written using rectangular coordinates. The body’s angular momentum comes from the cross-product of each mass element’s position vector with the cross-product of the body’s angular velocity and that position vector. This gives a compact way to describe how a solid structure moves in rotation. To work with the equation more easily, the XYZ axes can be chosen as a new set of rectangular axes. These axes may be inclined at any angle to the reference frame.

principle of impulse and moment

Impulse and Angular Momentum in Rigid Bodies

Impulse and angular momentum help describe a rigid body moving in a plane. This motion combines translation and rotation. The topic uses Newton's second law to connect force, momentum, and motion. For translational motion, the equation is written for the center of mass, labeled G. When this equation is multiplied by a small time interval, dt, and integrated, it gives the principle of linear impulse. This principle shows that a change in momentum is proportional to the impulse applied to the...

kinetic energy for a rigid body

Rigid Body Energy from Center and Rotation

Rigid body kinetic energy in planar motion can be written using the body’s center of mass and its rotation. The solid object moves in general planar motion, and its center of mass is marked at point G. To find the kinetic energy of the i-th particle, the relative velocity definition is used with the position vector rA from point A to that particle. The kinetic energy of the whole body is built from the particles. First, a scalar product is taken. Then the expression is written in integral form.

equation of motion for a rigid body

Rigid Body Motion: Force and Moment Balance

Rigid body motion is described with both translational motion and rotational motion about the center of mass, point G. The center of mass is the point where Newton's Second Law applies to translation. It gives the linear motion of the body. The same body also has rotational motion about point G. The combined moments about the center of mass equal the rate of change of angular momentum. A moment is the turning effect caused by a force, and an external force applied away from the center of mass...

euler equations of motion

Rigid Body Rotation in Euler’s Frame

Euler’s equations of motion describe how a rigid body rotates when measured in a moving frame attached to the body. The body rotates with angular velocity ω in an inertial frame, and the attached frame rotates with angular velocity Ω. Together, these two frames help describe the motion of the rigid body around its center of mass. The total moment about the center of mass is found by adding two parts. One part is the rate of change of angular momentum about the center of mass in the rotating...

torque free motion

Torque-free motion describes the movement of a rigid body when no external torques act on it. It can be seen in places with no outside forces or friction, such as outer space. Mars is one example of this kind of motion because it rotates in space without external torque. Mars is an axisymmetric object, which means it has an axis of symmetry. That symmetry defines the rotating z-axis. The rotating frame is set so that Mars&amp;#39;s center of mass is at the origin. This setup makes the moments...

key terms and concepts

Explore how Mars rotates as a torque-free, axisymmetric rigid body. Learn about angular momentum, precession, spin, and the angle theta in space.

Mars Spin Under No Torque | JoVE K12

JoVE Core Mechanical Engineering offers concise, easy-to-understand animated videos covering key topics such as equilibrium, forces, truss analysis, and structural mechanics. Explore their real-world applications, and witness these concepts in action through scientist-led experiments.

mechanical engineering

Mars Spin Under No Torque

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