Intriguing Problems with Static Friction on Stage (original) (raw)

The nature of friction: A critical assessment

Friction, 2013

Friction is an essential part of human experience. We need traction to walk, stand, work, and drive. At the same time, we need energy to overcome the resistance to motion, hence, too much friction costs excess energy to perform work, introducing inefficiencies. In the 21st century, we are facing the dual challenges of energy shortage and global warming from burning fossil fuels. Therefore, the ability to control friction has become a top priority in our world today. Yet our understanding of the fundamental nature of friction is still lacking. Friction has always been a subject of curiosity. Intensive study of the origin of friction began in the 16th century, after the pioneering work by Leonardo da Vinci. Yet progress in understanding the nature of friction has been slow, hampered by the lack of instrument to measure friction precisely. Ingenious experiments performed by Amontons, Coulomb, and others have yielded important insights to build the foundation of our understanding. Begin...

The Concept of Energy for Thermodynamics Friction System.pdf

Using the fluid energy equation, the first Law of thermodynamics for frictional system in the presence of gravity is formulated. According to this new model thermal energy is equal to pressure work beside kinetic energy in addition to work against gravity and frictional energy. This formula is verified experimentally by deriving a piston, moving inside a cylindrical tube, by water vapor. Three pistons made from AL, Cu, and fiberglass were used. The piston and cylinder system is inclined subtend the angles , 90 ,..., 20 , 10 , 0 in steps of 10 degree for each reading. The vapor thermal force tries to push the piston up word against frictional and gravity force. The relations between kinetic energy with net work done, frictional and gravity energy is in complete agreement with this new thermodynamic model.

Friction force: from mechanics to thermodynamics

European Journal of Physics, 2010

We study some mechanical problems in which a friction force is acting on the system. Using the fundamental concepts of state, time evolution and energy conservation we explain how to extend Newtonian mechanics to thermodynamics. We arrive at the two laws of thermodynamics and then apply them to investigate time evolution and heat transfer of some significant examples.

Theoretical Consideration About the Friction Law

2011

In the paper we are present some theoretical consideration about the effect of the friction in the sonic installation. To begin to the sonic pressure and the sonic flow we can demonstrate the effects of the friction.

Defining Friction Force: A Proposed Solution to a Textbook Problem

JOURNAL OF EDUCATION IN SCIENCE ENVIRONMENT AND HEALTH, 2019

This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden.

THE CONCEPT OF FORCE FOR THERMODYNAMIC FRICTIONAL SYSTEM.pdf

Anew thermodynamic first Law is proposed to account for the effect of friction and gravity force. This Law proposes existence of thermal impulsive force which produces pressure force and overcomes the frictional and gravity forces. This new Law is verified experimentally by allowing a cylindrical piston made from AL, Cu, and fiber glass to move under the action of water vapor thermal force. Strikingly the empirical relations between the different parameter and physical quantities concerning thermal, pressure, friction and gravity force agrees completely with the proposed theoretical ones.