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Kinetics in Angular Motion
Published in Emeric Arus, Biomechanics of Human Motion, 2017
Centripetal force coexists with another force named centrifugal force. The word comes from the Latin word “centrum” (center) and “fugere” to (flee). The centrifugal force has two slightly different manifestation forms:Reactive centrifugal force that occurs in reaction to a centripetal acceleration on a mass. This force is equal in magnitude to the centripetal force and is directed from the center of rotation. We can observe this force when we are sitting in a car. When the car is turning to the left, our body moves to the right. This motion to the right is the centrifugal force. In martial arts, an example of the centrifugal force manifestation is the aikido technique named “entering throw—negative” execution (Irimi-nage). Here, the executor (attacker) (Shite) guides the opponent in a rotary fashion. The defender (Uke) feels that the guiding force throws him away from the closeness of his attacker. Besides the attacker’s guiding force, the defender also feels the centrifugal force. More description about the centripetal and centrifugal forces can be found under Part IV.Pseudocentrifugal force appears when a rotating reference frame is used for analysis. The true frame acceleration is substituted by a pseudocentrifugal force that is exerted on all objects, and directed away from the axis of rotation.
An extension of Queiroz and Miyazawa's method for vertical stability in two-dimensional packing problems to deal with horizontal stability
Published in Engineering Optimization, 2019
Thiago A. Queiroz, Evandro C. Bracht, Flávio K. Miyazawa, Marco L. Bittencourt
In order to handle the cargo horizontal stability in two-dimensional packing problems, it is assumed that the packing is being transported by road and it is horizontally stable, therefore it is necessary to check if the packing is indeed stable. For the analysis under an inertial frame of reference (i.e. outside the cargo), the packing may experience situations in which the vehicle decreases its speed (i.e. decelerate), increases its speed (accelerate), and performs a curved path (i.e. centripetal acceleration) besides the impact of the wind pressure and the friction between items. The centripetal acceleration is responsible for the packing moving on the curved path, such that the packing (vehicle) follows the path because of the centripetal force. Notwithstanding, from the items' (driver's) point of view (i.e. a non-inertial frame of reference), they may experience a tendency to leave the road (i.e. their mass appears to push them outward from the curve due to inertia), which represents the reactive centrifugal force that balances with the centripetal one when equilibrium is met (Beer et al.2008; Hibbeler 2010).