Abstract
At this point in the Principia, Newton has defined his terms, he has stated his three axioms, and he has demonstrated their utility in solving problems involving multiple forces and bodies. Now, in the Scholium that follows, Newton provides a more general discourse, or meditation, on the power of his axioms. First, he briefly demonstrates how Galileo’s analysis of projectile motion relates to his own first and second laws. Next, he offers an explanation of how the motion of colliding bodies is affected by the elasticity of the bodies themselves. For this analysis, Newton expends considerable effort explaining how to account for the resistance of the air, a complication which can obscure otherwise intelligible results. He then proceeds to examine the relationship between his first and third laws of motion, using examples from magnetism and gravity. Interestingly, this raises the question as to whether they are, in fact, independent axioms. Are they? Finally, he shows how his third law suggests a general means for computing the mechanical advantage provided by machines of various sorts, such as screws, pulleys and wedges.
Keywords
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
The power and use of machines consists only in this, that by diminishing the velocity we may augment the force.
—Isaac Newton
This is a preview of subscription content, log in via an institution.
Buying options
Tax calculation will be finalised at checkout
Purchases are for personal use only
Learn about institutional subscriptionsNotes
- 1.
For example, PASCO’s Super Pulley (Model ME-9499), Pasco Scientific, Roseville, CA.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
Copyright information
© 2015 Springer Science+Business Media, LLC
About this chapter
Cite this chapter
Kuehn, K. (2015). The Third Law and the Power of Machines. In: A Student's Guide Through the Great Physics Texts. Undergraduate Lecture Notes in Physics. Springer, New York, NY. https://doi.org/10.1007/978-1-4939-1366-4_23
Download citation
DOI: https://doi.org/10.1007/978-1-4939-1366-4_23
Published:
Publisher Name: Springer, New York, NY
Print ISBN: 978-1-4939-1365-7
Online ISBN: 978-1-4939-1366-4
eBook Packages: Physics and AstronomyPhysics and Astronomy (R0)