Weighty issue

Physics World ◽  
2021 ◽  
Vol 34 (11) ◽  
pp. 28ii-28ii
Author(s):  
Alan Calverd ◽  
Tim Watson
Keyword(s):  
Centrifugal Force ◽  
Reaction Force ◽  
Centripetal Force ◽  
Definition Of

A response to Nick England’s letter “Going in circles” in which he discusses the change from teaching centrifugal force to teaching centripetal force, and the definition of weight being changed from the reaction force felt from the floor to the pull of gravity on an object.

Interpreters caught up in an ideological tug-of-war?

2019 ◽  
Vol 14 (1) ◽  
pp. 1-20 ◽  
Author(s):  
Chonglong Gu
Keyword(s):  
Centrifugal Force ◽  
Communication Process ◽  
Centripetal Force ◽  
The Press ◽  
Corpus Data ◽  
The Government

Abstract The interpreter-mediated Premier-Meets-the-Press Conferences are an institutional(ized) discursive event in China, permitting the Chinese premier to answer a range of potentially challenging and face-threatening questions from journalists. Arguably, this dynamic and interactive setting can be profitably conceptualized using Bakhtin’s notion of dialogized heteroglossia. As additional subjective actors in the triadic communication process, the government-affiliated interpreters are caught up in an ideological tug-of-war between the government and (foreign) journalists. That is, there is often a centripetal force pulling toward Beijing’s official positions and stances (the central, unitary and authoritative) and simultaneously a centrifugal force exerted by (foreign) journalists who pose sensitive and adversarial questions (toward the heteroglossic and peripheral away from the center). Manual CDA on 20 years’ corpus data illustrates the interpreters’ tendency to align with the government’s official positions, soften the journalists’ questions and (re)construct a more desirable image for Beijing.

scholarly journals INERTIAL FORCES AS VIEWED FROM THE ADM SLICING AND THEIR BEHAVIOUR FOR PARTICLES IN NON-CIRCULAR GEODESICS

2002 ◽  
Vol 17 (28) ◽  
pp. 1835-1845 ◽  
Author(s):  
A. R. PRASANNA
Keyword(s):  
Black Holes ◽  
Angular Velocity ◽  
Radial Velocity ◽  
Centrifugal Force ◽  
Test Particle ◽  
Physical Parameters ◽  
Inertial Forces ◽  
Shift Vector ◽  
Definition Of ◽  
Lapse Function

Considering the definition of inertial forces acting on a test particle, following non-circular geodesics, in static and stationary space–times, we show that the centrifugal force reversal occurs only in the case of particles following prograde orbits around black holes. We first rewrite the covariant expressions for the acceleration components in terms of the lapse function, shift vector and the three-metric γij, using the ADM 3 + 1 splitting and use these, for different cases as given by pure radial motion, pure azimuthal motion and the general non-circular motion. It is found that the reversal occurs between 2m and 3m, only when the azimuthal angular velocity of the particle supersedes the radial velocity, which indeed depends upon the physical parameters E, ℓ and the Kerr parameter a.

Identification of Balanced State Domain for Single-Support Legged Mechanism

2011 ◽  
Author(s):  
Joo H. Kim ◽  
Chang B. Joo
Keyword(s):  
Reaction Force ◽  
Sufficient Conditions ◽  
Optimization Method ◽  
Normal Reaction ◽  
System Parameters ◽  
Zero Moment ◽  
Definition Of ◽  
Legged Mechanism ◽  
Necessary And Sufficient ◽  
General Balance

Balancing is one of the most important issues of biped mechanism. In this presentation, an enhanced definition of a balanced state is proposed and the balanced state manifold for single-support legged mechanism is calculated by using constrained optimization method. The algorithm iteratively solves for the maximum and minimum velocities for a set of joint variables and actuation capacities. In addition to the system parameters, the necessary and sufficient conditions for balancing, such as the Zero-Moment Point, positive normal reaction force, friction, and final static equilibrium, are implemented as constraints. The calculated balanced state manifold can be used as general balance criteria for the single-support legged mechanism. The proposed framework can also be extended to form the balanced state manifold of systems with higher complexity.

Fluid Particle’s Rotational Speed at the Trailing Edge of Impeller Outlet of Centrifugal Pump

2003 ◽  
Author(s):  
Takaharu Tanaka
Keyword(s):  
Centrifugal Force ◽  
Flow Rate ◽  
Mechanical Energy ◽  
Fluid Particle ◽  
Rotating Flow ◽  
Centripetal Force ◽  
Impeller Blade ◽  
Flow Passage ◽  
Impeller Outlet ◽  
Pump Head

Mechanical force caused by mechanical energy acts real and imaginary forces on impeller blade. Therefore, impeller blade moves in the direction of real force, straightly forward in the direction of tangent perpendicular to rotational radius and the direction of imaginary force, circularly forward in the direction of tangent perpendicular to rotational radius. Former real movement causes on fluid particle radial outward movement, resulting to flow rate Q. Latter imaginary movement causes on fluid particle a rotational motion under the external centripetal and imaginary centrifugal force, resulting to pump head. Pump head is equivalent to external centripetal force and balanced with imaginary centrifugal force in the rotating flow passage.

Fluid Particles Straightly Forward and Circularly Forward Movements in the Direction of Tangent at Trailing Edge of Impeller Outlet in Centrifugal Turbomachinery

2003 ◽  
Author(s):  
Takaharu Tanaka
Keyword(s):  
Centrifugal Force ◽  
Flow Rate ◽  
Rotational Motion ◽  
Mechanical Energy ◽  
Centripetal Force ◽  
Impeller Outlet ◽  
Water Turbine ◽  
Fluid Particles ◽  
Centripetal Forces ◽  
Acting Force

Flow rate, which is caused in the direction radial outward in pump and radial inward in water turbine, is caused by the fluid particles straightly forward tangential movement in the direction of acting force perpendicular to impeller blades rotational radius. Impeller blades rotational motion is caused under the radial balance of centrifugal and centripetal forces. Centrifugal force is caused by the transferred energy from mechanical to hydraulic energy in pump and from hydraulic to mechanical energy in water turbine. Centripetal force is equivalent to discharge head in pump and equivalent to suction head in water turbine.

On Centrifugal Force

1946 ◽  
Vol 30 (288) ◽  
pp. 17-18
Author(s):  
E. G. Phillips
Keyword(s):  
Centrifugal Force ◽  
Easy Access ◽  
Centripetal Force ◽  
Elementary Mechanics ◽  
Elementary Textbooks

What is centrifugal force? On selecting at random about a dozen elementary textbooks on Mechanics to find a definition, I was pleasantly surprised to discover (unless I have inadvertently missed it in any of them) that only four of them mention the name “centrifugal force”, and two only of these four mention “centripetal force” as well. No doubt if I had had easy access to textbooks written for and used by engineers, the results would have been different; but as I am concerned only about mathematical students, I have not troubled to pursue my search except in the kind of textbooks likely to be used in schools which teach elementary mechanics as a branch of mathematics.

scholarly journals A Noise-Immune Kalman Filter and Modelling forPedestrian Traffic Loads

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Yanan Gao ◽  
Ningbo Peng ◽  
Jitao Tang ◽  
Yun Dong ◽  
Weidong Zhang ◽  
...  
Keyword(s):  
Ground Reaction Force ◽  
System Modeling ◽  
Reaction Force ◽  
Discrete State ◽  
Design Load ◽  
Traffic Loads ◽  
Oscillate System ◽  
Definition Of ◽  
Discrete State Space ◽  
Slender Structures

The definition of design load with walking crowd excitation on these slender structures is a significant problem to human-induced vibration. To capture the characteristics of walking crowd loads, this article researches both the ground reaction force and ground reaction moment for 36 healthy adults. Firstly, a oscillate system modeling walking leg is used to build a governing equation, which further transformed into the discrete state space. Then the Kalman method is applied to filter the noises for the measured ground reaction force, which can well remove the noises hiding in the measured signals. In addition, the Fourier series are used to model the ground reaction force and ground reaction moment, and the first six corresponding coefficients are obtained and analyzed. This work comprehensively explores the excitation force and moment from walking pedestrian feet. The result of this study provides the reference of load design for these slender structures such as footbridges, grandstands, or stations under crowd excitation.

scholarly journals Macrokinetics and Practical Application of SHS Process under the Conditions of a Centrifugal Force

2011 ◽  
Vol 13 (3-4) ◽  
pp. 155
Author(s):  
G. Ksandopulo ◽  
A. Baydeldinova ◽  
A. Ainabayev ◽  
M. Arkhipov ◽  
K. Omarova
Keyword(s):  
High Temperature ◽  
Centrifugal Force ◽  
Temperature Effects ◽  
Wide Spectrum ◽  
Thermal Characteristics ◽  
Ceramic Materials ◽  
Centripetal Force ◽  
Practical Application ◽  
Centrifugal Acceleration ◽  
Oxide Systems

Extension of the possibilities of using SHS based on combustion with the aim to obtain impurity-free alloys, special ceramic materials with enhanced strength and thermal characteristics due to the effect of centrifugal acceleration is a practical task of this investigation. The use of a centripetal force in the method of SHS in layer oxide systems opens the prospect of using high temperature effects for creation of a wide spectrum of target products differing in composition and properties.

scholarly journals Vibration Feedforward Compensation for Magnetically Suspended Control and Sensitive Gyroscope with Spherical Rotor

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Qiang Liu ◽  
Heng Li ◽  
Cong Peng ◽  
Sha Sheng ◽  
Zhaojing Yin ◽  
...  
Keyword(s):  
Centrifugal Force ◽  
Attitude Control ◽  
High Speed ◽  
Reaction Force ◽  
Magnetic Bearing ◽  
Dynamic Reaction ◽  
Optimal Sequence ◽  
Vibration Displacement ◽  
Control Moment ◽  
Working Principle

Magnetically suspended control and sensitive gyroscope (MSCSG) with two capabilities including attitude control and attitude measurement is promising in meeting the requirements of novel spacecraft. When the momentum vector of a high-speed rotor suspended in five directions is tilted by Lorentz force-type magnetic bearing, the instantaneous large control moment is obtained. The spacecraft attitude can be sensed by a high-speed rotor without deflection interference torque. In this paper, a novel MSCSG with sphere rotor is presented, and its spherical structure and working principle are introduced. The magnetic bearing-rotor dynamic model is established based on Newton’s second law and the gyrokinetic equations. The generating mechanism of three interferences, including bearing dynamic reaction force, deflection torque, and centrifugal force, is analyzed. The feedforward compensation control against three interferences for MSCSG is adopted, and the loading sequence of three interferences is simulated. The optimal sequence of bearing dynamic reaction force, deflection torque, and centrifugal force is used. The radial and axial vibration displacement amplitudes are reduced from 20.8 μm and 31.7 μm to 9.4 μm and 14.9 μm, respectively. The experimental results are in good agreement with the simulation, which indicates the MSCSG rotor unbalance vibration is suppressed effectively by the feedforward compensation method.

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