Newton's Third Law: Action and Reaction | Physics Explained 4.4

How does a rocket speed up in empty space, with nothing to push against? This lesson covers Newton's third law: every force has an equal and opposite partner. Skaters pushing apart, why action and reaction never cancel (a swimmer pushing off a wall), and why to move forward you push something backward. Three important forces: the normal force (and the classic trap of thinking weight and normal force are a pair), tension, and thrust. Then a problem-solving strategy and a full worked example: a teacher pushing a cart of equipment. Ends with a summary of all three laws. Chapters: 0:00 Intro 0:58 Newton's third law 1:44 Equal forces, unequal accelerations 2:15 Why don't they cancel? 3:13 Push back to go forward 3:52 The normal force 5:17 Tension 6:07 Thrust 6:46 Solving problems with Newton's laws 7:30 Worked example: the equipment cart 9:20 Recap 10:05 Check yourself 11:16 Up next Physics Explained, Chapter 4: Forces and Newton's Laws of Motion (lesson 4 of 4) Adapted from Physics by OpenStax (https://openstax.org/details/books/ph..., licensed under CC BY 4.0 (https://creativecommons.org/licenses/.... The animations and narration are original to Prime Mover. OpenStax is not affiliated with this channel and does not endorse it. Prime Mover: learn it, build it, share it.