A Friction-Bearing Calorimeter Experiment Yielding Joule's Constant

1996 ◽  
Vol 24 (4) ◽  
pp. 235-242 ◽  
Author(s):  
R. S. Mullisen
Keyword(s):  
Kinetic Energy ◽  
Potential Energy ◽  
Laboratory Experiment ◽  
Heat Loss ◽  
Gravitational Potential ◽  
Data Reduction ◽  
Gravitational Potential Energy ◽  
Experimental Procedure ◽  
Friction Bearing ◽  
Elastic Potential Energy

A simple, friction-bearing calorimeter that yields Joule's constant is described in this paper. The apparatus is easily constructed at minimal expense and may be used as a laboratory experiment. Although the design is very simple, the experimental procedure and data reduction analysis account for gravitational potential energy, elastic potential energy, translational and rotational kinetic energy, and heat loss. The result is a Joule's constant value accurate within 3%.

Tracker-assisted modelling: simultaneous validation of the conservation law of energy and the work-energy theorem

2021 ◽  
Vol 57 (1) ◽  
pp. 015012
Author(s):  
Unofre B Pili ◽  
Renante R Violanda
Keyword(s):  
Kinetic Energy ◽  
Potential Energy ◽  
Gravitational Potential ◽  
Conservation Law ◽  
Gravitational Potential Energy ◽  
Time Data ◽  
Home Based ◽  
Basic Physics ◽  
Free Falling ◽  
Work Done

Abstract The video of a free-falling object was analysed in Tracker in order to extract the position and time data. On the basis of these data, the velocity, gravitational potential energy, kinetic energy, and the work done by gravity were obtained. These led to a rather simultaneous validation of the conservation law of energy and the work–energy theorem. The superimposed plots of the kinetic energy, gravitational potential energy, and the total energy as respective functions of time and position demonstrate energy conservation quite well. The same results were observed from the plots of the potential energy against the kinetic energy. On the other hand, the work–energy theorem has emerged from the plot of the total work-done against the change in kinetic energy. Because of the accessibility of the setup, the current work is seen as suitable for a home-based activity, during these times of the pandemic in particular in which online learning has remained to be the format in some countries. With the guidance of a teacher, online or face-to-face, students in their junior or senior high school—as well as for those who are enrolled in basic physics in college—will be able to benefit from this work.

scholarly journals Walking in simulated reduced gravity: mechanical energy fluctuations and exchange

1999 ◽  
Vol 86 (1) ◽  
pp. 383-390 ◽  
Author(s):  
Timothy M. Griffin ◽  
Neil A. Tolani ◽  
Rodger Kram
Keyword(s):  
Kinetic Energy ◽  
Potential Energy ◽  
Gravitational Potential ◽  
Inverted Pendulum ◽  
Mechanical Energy ◽  
Center Of Mass ◽  
Metabolic Cost ◽  
Metabolic Energy ◽  
Gravitational Potential Energy ◽  
Reduced Gravity

Walking humans conserve mechanical and, presumably, metabolic energy with an inverted pendulum-like exchange of gravitational potential energy and horizontal kinetic energy. Walking in simulated reduced gravity involves a relatively high metabolic cost, suggesting that the inverted-pendulum mechanism is disrupted because of a mismatch of potential and kinetic energy. We tested this hypothesis by measuring the fluctuations and exchange of mechanical energy of the center of mass at different combinations of velocity and simulated reduced gravity. Subjects walked with smaller fluctuations in horizontal velocity in lower gravity, such that the ratio of horizontal kinetic to gravitational potential energy fluctuations remained constant over a fourfold change in gravity. The amount of exchange, or percent recovery, at 1.00 m/s was not significantly different at 1.00, 0.75, and 0.50 G (average 64.4%), although it decreased to 48% at 0.25 G. As a result, the amount of work performed on the center of mass does not explain the relatively high metabolic cost of walking in simulated reduced gravity.

scholarly journals Feedback of outflows in the Taurus Molecular Cloud

2012 ◽  
Vol 8 (S292) ◽  
pp. 47-47
Author(s):  
Huixian Li ◽  
Di Li ◽  
Rendong Nan
Keyword(s):  
Kinetic Energy ◽  
Potential Energy ◽  
Gravitational Potential ◽  
Molecular Cloud ◽  
Feedback Effect ◽  
Total Kinetic Energy ◽  
Gravitational Potential Energy ◽  
Taurus Molecular Cloud

AbstractWe collected 27 outflows from the literature and found 8 new ones in the FCRAO CO maps of the Taurus molecular cloud. The total kinetic energy of the 35 outflows is found to be about 3% of the gravitational potential energy from the whole cloud. The feedback effect due to the outflows is minor in Taurus.

Mechanics of locomotion in lizards.

1997 ◽  
Vol 200 (16) ◽  
pp. 2177-2188 ◽  
Author(s):  
C T Farley ◽  
T C Ko
Keyword(s):  
Kinetic Energy ◽  
Potential Energy ◽  
Gravitational Potential ◽  
Inverted Pendulum ◽  
Mechanical Energy ◽  
Center Of Mass ◽  
Gravitational Potential Energy ◽  
Lateral Bending ◽  
Walking Gait ◽  
Bending Force

Lizards bend their trunks laterally with each step of locomotion and, as a result, their locomotion appears to be fundamentally different from mammalian locomotion. The goal of the present study was to determine whether lizards use the same two basic gaits as other legged animals or whether they use a mechanically unique gait due to lateral trunk bending. Force platform and kinematic measurements revealed that two species of lizards, Coleonyx variegatus and Eumeces skiltonianus, used two basic gaits similar to mammalian walking and trotting gaits. In both gaits, the kinetic energy fluctuations due to lateral movements of the center of mass were less than 5% of the total external mechanical energy fluctuations. In the walking gait, both species vaulted over their stance limbs like inverted pendulums. The fluctuations in kinetic energy and gravitational potential energy of the center of mass were approximately 180 degrees out of phase. The lizards conserved as much as 51% of the external mechanical energy required for locomotion by the inverted pendulum mechanism. Both species also used a bouncing gait, similar to mammalian trotting, in which the fluctuations in kinetic energy and gravitational potential energy of the center of mass were nearly exactly in phase. The mass-specific external mechanical work required to travel 1 m (1.5 J kg-1) was similar to that for other legged animals. Thus, in spite of marked lateral bending of the trunk, the mechanics of lizard locomotion is similar to the mechanics of locomotion in other legged animals.

On the Perfect Gravity-Balance of a Spatial N-DOF Manipulator Based on the Localized Pseudo-Base

2009 ◽  
Author(s):  
Po-Yang Lin ◽  
Win-Bin Shieh ◽  
Dar-Zen Chen
Keyword(s):  
Exact Solution ◽  
Potential Energy ◽  
Gravitational Potential ◽  
Rotation Axis ◽  
Industrial Robot ◽  
Elastic Potential ◽  
Gravitational Potential Energy ◽  
Mass Center ◽  
Elastic Potential Energy ◽  
Six Dof

This paper offers an exact solution for the perfect gravity-balance of a class of spatial manipulators with no translational joints. The methodology used is based on the concept of conservation of the gravitational and elastic potential energy of the system. The overall gravitational potential energy of a serial-connected, n-link manipulator is identified to be contributed by n subsystems, where each subsystem is kinematically equivalent to one of the primary links of the manipulator, and possesses the accumulated mass of its post-connected links with a fixed mass center located on the subsystem. The gravitational potential energy of such a subsystem can be fully balanced by the elastic potential energy of the spring fitted between the link and its adjacent pseudo-base. Since the rotation axis of the pseudo-base is required to be in the direction of gravity, n serial-connected RSSR modules are constituted along the primary chain of the manipulator to provide a pseudo-base for each of the primary links. With one linear, zero-free-length spring fitted between each of the primary links of the manipulator and its associated pseudo-base, a static equilibrium of the considered mechanism in any configuration can be reached. A numerical example of the model of a six-DOF industrial robot has demonstrated the success of the proposed methodology.

Design of Perfectly Static-Balanced One-DOF Planar Linkage With Revolute Joint Only

2008 ◽  
Author(s):  
Po-Yang Lin ◽  
Win-Bin Shieh ◽  
Dar-Zen Chen
Keyword(s):  
Potential Energy ◽  
Gravitational Potential ◽  
Elastic Potential ◽  
Gravitational Potential Energy ◽  
Single Degree Of Freedom ◽  
Parallel Links ◽  
Parallel Motion ◽  
Systematic Methodology ◽  
Elastic Potential Energy ◽  
Spring Constants

A systematic methodology for the design of a statically balanced, single degree-of-freedom planar linkage is presented. This design methodology is based on the concept of conservation of potential energy, formulated by the use of complex number notations as link vectors of the linkage. By incorporating the loop closure equations, the gravitational potential energy of the system can be simplified as the function of the vectors of all ground-adjacent links. The balance of the gravitational potential energy of the system is then accomplished by the elastic potential energy of a zero free-length spring on each ground-adjacent link of the linkage. As a result, spring constants and installation configurations of the ground-attached springs are obtained. Since the variation of the gravitational potential energy of the linkage at all configurations can be fully compensated by that of the elastic potential energy of springs, this methodology provides an exact solution for the design of a general spring balancing mechanism without auxiliary parallel links. Illustrations of the methodology are successfully demonstrated by the spring balancing designs of a general Stephenson-III type six-bar linkage and a Watt-I type six-bar linkage with parallel motion.

scholarly journals Gravitational Potential Energy Balance for the Thermal Circulation in a Model Ocean

2006 ◽  
Vol 36 (7) ◽  
pp. 1420-1429 ◽  
Author(s):  
Rui Xin Huang ◽  
Xingze Jin
Keyword(s):  
Energy Balance ◽  
Equation Of State ◽  
Kinetic Energy ◽  
Potential Energy ◽  
Gravitational Potential ◽  
Mechanical Energy ◽  
Vertical Mixing ◽  
Gravitational Potential Energy ◽  
Thermal Circulation ◽  
Model Ocean

Abstract The gravitational potential energy balance of the thermal circulation in a simple rectangular model basin is diagnosed from numerical experiments based on a mass-conserving oceanic general circulation model. The vertical mixing coefficient is assumed to be a given constant. The model ocean is heated/cooled from the upper surface or bottom, and the equation of state is linear or nonlinear. Although the circulation patterns obtained from these cases look rather similar, the energetics of the circulation may be very different. For cases of differential heating from the bottom with a nonlinear equation of state, the circulation is driven by mechanical energy generated by heating from the bottom. On the other hand, circulation for three other cases is driven by external mechanical energy, which is implicitly provided by tidal dissipation and wind stress. The major balance of gravitational energy in this model ocean is between the source of energy due to vertical mixing and the conversion from kinetic energy at low latitudes and the sink of energy due to convection adjustment and conversion to kinetic energy at high latitudes.

Design of Perfectly Statically Balanced One-DOF Planar Linkages With Revolute Joints Only

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
Po-Yang Lin ◽  
Win-Bin Shieh ◽  
Dar-Zen Chen
Keyword(s):  
Potential Energy ◽  
Gravitational Potential ◽  
Elastic Potential ◽  
Gravitational Potential Energy ◽  
Revolute Joints ◽  
Parallel Links ◽  
Parallel Motion ◽  
Elastic Potential Energy ◽  
Planar Linkages ◽  
Spring Constants

A systematic methodology for the design of a statically balanced, single degree-of-freedom planar linkage is presented. This design methodology is based on the concept of conservation of potential energy, formulated by the use of complex number notations as link vectors of the linkage. By incorporating the loop closure equations and the kinematic constraints, the gravitational potential energy of the system can be formulated as the function of the vectors of all ground-adjacent links. The balance of the gravitational potential energy of the system is then accomplished by the elastic potential energy of a zero free-length spring on each ground-adjacent link of the linkage. As a result, spring constants and installation configurations of the ground-attached springs are obtained. Since the variation in the gravitational potential energy of the linkage at all configurations can be fully compensated by that of the elastic potential energy of the ground-attached springs, this methodology provides an exact solution for the design of a general spring balancing mechanism without auxiliary parallel links. Illustrations of the methodology are successfully demonstrated by the spring balancing designs of a general Stephenson-III type six-bar linkage and a Watt-I type six-bar linkage with parallel motion.

scholarly journals A gravity balancing assistant arm design in 3-D for rehabilitation of stroke patients

2021 ◽  
Vol 336 ◽  
pp. 02016
Author(s):  
Jianbo Shu ◽  
Xuehua Tang ◽  
Fan Niu ◽  
Changchun Xia ◽  
Congcong Shi
Keyword(s):  
Potential Energy ◽  
Gravitational Potential ◽  
Energy Equation ◽  
Elastic Potential ◽  
Gravitational Potential Energy ◽  
Practical Application ◽  
Stroke Patients ◽  
Rigid Rods ◽  
Motion Process ◽  
Elastic Potential Energy

A gravity balancing assistant arm design in 3-D is a mechanical mechanism consisted of springs, rigid rods, joints and sliders, which can be modified to the geometry and inertia of the arm of stroke patients. This mechanism is designed without any controllers and motors, based solely on mechanical principles, to achieve a relative balance of gravitational potential energy and elastic potential energy, thereby reducing the burden on the arm of a stroke patient to facilitate rehabilitation. To achieve this function, first, the center of gravity of the patient’s arm will be positioned, and then the mounting position of the spring on the assistant arm will be determined. In this paper, the following objectives will be achieved: (i) the calculation of the gravitational potential energy and the elastic potential energy in the mechanism (ii) the simplification of the potential energy equation and the elimination of the coefficient of the items related to the angle. (iii) The comparison between 2-D and 3-D cases of the mechanism. (iv) The motion process of simulating the mechanism using MATLAB (v) Using MATLAB to create the energy plots (vi) Using SolidWorks to construct the prototype of the mechanism (vii) Describe the practical application and future extensions of this mechanism.

scholarly journals The phase shift between potential and kinetic energy in human walking

2020 ◽  
Vol 223 (21) ◽  
pp. jeb232645
Author(s):  
Giovanni A. Cavagna ◽  
Mario A. Legramandi
Keyword(s):  
Kinetic Energy ◽  
Potential Energy ◽  
Gravitational Potential ◽  
Sagittal Plane ◽  
Center Of Mass ◽  
Phase Relationship ◽  
Gravitational Potential Energy ◽  
External Work ◽  
Unit Distance ◽  
Factors Affecting

ABSTRACTIt is known that mechanical work to sustain walking is reduced, owing to a transfer of gravitational potential energy into kinetic energy, as in a pendulum. The factors affecting this transfer are unclear. In particular, the phase relationship between potential and kinetic energy curves of the center of mass is not known. In this study, we measured this relationship. The normalized time intervals α, between the maximum kinetic energy in the sagittal plane (Ek) and the minimum gravitational potential energy (Ep), and β, between the minimum Ek and the maximum Ep, were measured during walking at various speeds (0.5–2.5 m s−1). In our group of subjects, α=β at 1.6 m s−1, indicating that, at this speed, the time difference between Ep and Ek extremes is the same at the top and the bottom of the trajectory of the center of mass. It turns out that, at the same speed, the work done to lift the center of mass equals the work to accelerate it forwards, the Ep–Ek energy transfer approaches a maximum and the mass-specific external work per unit distance approaches a minimum.

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