Editing Force (section)

=== Defining "force" ===
Some textbooks use Newton's second law as a ''definition'' of force.<ref>{{Cite book |last1=Landau |first1=L. D. |author-link=Lev Landau |last2=Akhiezer |author2-link=Aleksander Akhiezer |first2=A. I. |last3=Lifshitz |first3=A. M. |author3-link=Evgeny Lifshitz |title=General Physics; mechanics and molecular physics |publisher=Pergamon Press |year=1967 |location=Oxford |edition= |isbn=978-0-08-003304-4 |url-access=registration |url=https://archive.org/details/generalphysicsme0000land_d9j0 }}
Translated by: J. B. Sykes, A. D. Petford, and C. L. Petford. {{LCCN|67-30260}}. In section 7, pp. 12–14, this book defines force as ''dp/dt''.</ref><ref>{{Cite book |last1=Kibble |first1=Tom W. B. |last2=Berkshire |first2=Frank H. |title=Classical Mechanics |publisher=Imperial College Press |year=2004 |location=London |edition=5th |isbn=1860944248}}
According to page 12, "[Force] can of course be introduced, by defining it through Newton's second law".</ref><ref>{{Cite book |last1=de Lange |first1=O. L. |last2=Pierrus |first2=J. |title=Solved Problems in Classical Mechanics |publisher=Oxford University Press |year=2010 |location=Oxford |edition= |isbn=978-0-19-958252-5}}
According to page 3, "[Newton's second law of motion] can be regarded as defining force".</ref><ref>{{Cite book|last1=José|first1=Jorge V.|url=https://www.worldcat.org/oclc/857769535|title=Classical dynamics: A Contemporary Approach|last2=Saletan|first2=Eugene J.|date=1998|publisher=Cambridge University Press|isbn=978-1-139-64890-5|location=Cambridge [England]|oclc=857769535|author-link=Jorge V. José |page=9}}</ref> However, for the equation <math>\mathbf{F} = m\mathbf{a}</math> for a constant mass <math>m</math> to then have any predictive content, it must be combined with further information.<ref>{{Cite book|last1=Frautschi|first1=Steven C.|title=The Mechanical Universe: Mechanics and Heat|title-link=The Mechanical Universe|last2=Olenick|first2=Richard P.|last3=Apostol|first3=Tom M.|last4=Goodstein|first4=David L.|date=2007|publisher=Cambridge University Press|isbn=978-0-521-71590-4|edition=Advanced|location=Cambridge [Cambridgeshire]|oclc=227002144|author-link=Steven Frautschi|author-link3=Tom M. Apostol|author-link4=David L. Goodstein|page=134}}</ref><ref name=FeynmanVol1 />{{rp|((12-1))}} Moreover, inferring that a force is present because a body is accelerating is only valid in an inertial frame of reference.<ref name=Kleppner />{{rp|59}} The question of which aspects of Newton's laws to take as definitions and which to regard as holding physical content has been answered in various ways,<ref name="thornton-marion">{{cite book|first1=Stephen T. |last1=Thornton |first2=Jerry B. |last2=Marion |title=Classical Dynamics of Particles and Systems |edition=5th |publisher=Thomson Brooks/Cole |isbn=0-534-40896-6 |year=2004 |pages=49–50}}</ref><ref name=":0">{{cite book |author-last1=Landau |author-first1=Lev D. |title=Mechanics |author-last2=Lifshitz |author-first2=Evgeny M. |date=1969 |publisher=[[Pergamon Press]] |isbn=978-0-080-06466-6 |edition=2nd |series=[[Course of Theoretical Physics]] |volume=1 |translator-last1=Sykes |translator-first1=J. B. |author-link1=Lev Landau |author-link2=Evgeny Lifshitz |translator-last2=Bell |translator-first2=J. S. |translator-link2=John Stewart Bell}}</ref>{{Rp|pages=vii}} which ultimately do not affect how the theory is used in practice.<ref name="thornton-marion"/> Notable physicists, philosophers and mathematicians who have sought a more explicit definition of the concept of force include [[Ernst Mach]] and [[Walter Noll]].<ref>{{cite book |last=Jammer |first=Max |author-link=Max Jammer |title=Concepts of Force: A study in the foundations of dynamics |year=1999 |publisher=Dover Publications |location=Mineola, NY |isbn=978-0486406893 |pages=220–222 |edition=Facsim.}}</ref><ref>{{cite web |first=Walter |last=Noll |title=On the Concept of Force |url=http://www.math.cmu.edu/~wn0g/Force.pdf |publisher=Carnegie Mellon University |date=April 2007 |access-date=28 October 2013}}</ref>