rigid

(adjective)

Stiff, rather than flexible.

Examples of rigid in the following topics:

  • Connected Objects

    • The simplest form of connection is a perfectly rigid connection.
    • Thus it can be said that a perfectly rigid connection makes two objects into one large object.
    • Of course, perfectly rigid connections do not exist in nature.
    • However, many materials are sufficiently rigid, so that using the perfectly rigid approximation is useful for simplicity's sake.
    • Analyze the affect a rigid connection has on the movement of objects

  • The Physical Pendulum

    • Gravity acts through the center of mass of the rigid body.
    • For illustration, let us consider a uniform rigid rod, pivoted from a frame as shown (see ).
    • The moment of inertia of the rigid rod about its center is:
    • However, it is not independent of the mass distribution of the rigid body.
    • A rigid rod with uniform mass distribution hangs from a pivot point.

  • Center of Mass and Translational Motion

    • We considered that actual three dimensional rigid bodies move such that all constituent particles had the same motion (i.e., same trajectory, velocity and acceleration).
    • By doing this, we have essentially considered a rigid body as a point particle.
    • This concept of COM, therefore, eliminate the complexities otherwise present in attempting to describe motions of rigid bodies.
    • We describe the translational motion of a rigid body as if it is a point particle with mass m located at COM.

  • General Problem-Solving Tricks

    • rigid extended.
    • A force on an extended rigid body is asliding vector.
    • non-rigid extended.
    • A force on a non-rigid body is a bound vector.
    • The body: This is usually sketched in a schematic way depending on the body - particle/extended, rigid/non-rigid - and on what questions are to be answered.

  • Motion of the Center of Mass

    • We can describe the translational motion of a rigid body as if it is a point particle with the total mass located at the COM—center of mass.
    • We can describe the translational motion of a rigid body as if it is a point particle with the total mass located at the center of mass (COM).
    • Derive the center of mass for the translational motion of a rigid body

  • Poiseuille's Equation and Viscosity

    • Poiseuille's equation can be used to determine the pressure drop of a constant viscosity fluid exhibiting laminar flow through a rigid pipe.
    • Laminar flow is often encountered in common hydraulic systems, such as where fluid flow is through an enclosed, rigid pipe; the fluid is incompressible, has constant viscosity, and the Reynolds number is below this lower critical threshold value.
    • Can be used to determine the pressure drop of a constant viscosity fluid exhibiting laminar flow through a rigid pipe.

  • Kinetic Energy and Work-Energy Theorem

    • This definition can be extended to rigid bodies by defining the work of the torque and rotational kinetic energy.

  • Shape

    • In geometry, two subsets of a Euclidean space have the same shape if one can be transformed to the other by a combination of translations, rotations (together also called rigid transformations), and uniform scalings.

  • Constant Pressure and Volume

    • We may say that the system is dynamically insulated, by a rigid boundary, from the environment.

  • A General Approach

    • There is no rigid procedure that will work every time.