Physics Help Forum action-reaction

 Kinematics and Dynamics Kinematics and Dynamics Physics Help Forum

 Jul 9th 2017, 12:59 AM #1 Junior Member   Join Date: Jul 2017 Posts: 27 action-reaction Hello, buddies! I read a piece of text, where I found a puzzling interpretation of Newton's third law (F1=-F2). The author gives the following representation: F=Rv(m1m2/l^2) R - reaction; m1, m2 - masses; v - velocity of reaction; l - distance between the two objects. Please, help me with explanations about the equation, suggestons about its derivation? I will be grateful for every comment. The formula reminds me of Newton's law of universal gravitation: F=k(m1m2/l^2) F - force between the masses; k - gravitational constant; m1, m2 - masses; l - distance between the centers of the masses. But what is the reason for replacing k (gravitational constant) with Rv .... any ideas? It is puzzling matter, this author keeps me thrown in confusion...
Jul 9th 2017, 06:00 PM   #2
Senior Member

Join Date: Aug 2010
Posts: 272
 Originally Posted by DesertFox Hello, buddies! I read a piece of text, where I found a puzzling interpretation of Newton's third law (F1=-F2). The author gives the following representation: F=Rv(m1m2/l^2) R - reaction; m1, m2 - masses; v - velocity of reaction; l - distance between the two objects.
I would like to have more information about this because it makes no sense! In particular, what does "R- reaction" mean? What units does "reaction" have? Is F a force? If so then it has units mass times distance over time^2. Since v(m1m2)/l^2 has units of mass^2 over (time times distance), R would have to have units of distance^2 over (time times mass). I don't know any quantity that has those distances!

 Please, help me with explanations about the equation, suggestons about its derivation? I will be grateful for every comment. The formula reminds me of Newton's law of universal gravitation: F=k(m1m2/l^2) F - force between the masses; k - gravitational constant; m1, m2 - masses; l - distance between the centers of the masses. But what is the reason for replacing k (gravitational constant) with Rv .... any ideas? It is puzzling matter, this author keeps me thrown in confusion...
Was this from a book or journal article? Could you give us a citation?

 Thread Tools Display Modes Linear Mode

 Similar Physics Forum Discussions Thread Thread Starter Forum Replies Last Post jlyu002 Kinematics and Dynamics 6 May 21st 2017 10:21 PM ndung Theoretical Physics 4 Mar 31st 2014 03:58 PM s3a Kinematics and Dynamics 1 Apr 18th 2009 10:34 PM jot321 Kinematics and Dynamics 1 Oct 10th 2008 09:47 AM