Chapter 4 NEWTON’S 3 rd LAW OF MOTION Action – Reaction Pairs Examples Figures from OpenStax College, ancillaries to College Physics. OpenStax College. 21 June 2012. http :// cnx.org/content/col11406/latest/ , licensed under a CC 4.0 International License, unless otherwise specified.
1. Chapter 4 NEWTONS 3rd LAW OF MOTION Action Reaction Pairs
Examples Figures from OpenStax College, ancillaries to College
Physics. OpenStax College. 21 June 2012.
http://cnx.org/content/col11406/latest/, licensed under a CC 4.0
International License, unless otherwise specified.
2. Newtons 3rd Law For every action, there is an equal and
opposite reaction. NewtonsLawOfUniversalGravitation.svg; by
Dna-Dennis derivative work: Onio72 (talk)) [CC BY 3.0
Unported]
3. Example 1 swimmer pushing on a wall
4. Example 2 Person pushing a cart
5. Check Your Understanding 1 While driving down the road, a
firefly strikes the windshield of a bus and makes a quite obvious
mess in front of the face of the driver. The firefly hit the bus
and the bus hits the firefly. Which of the two forces is greater:
the force on the firefly or the force on the bus?
http://www.physicsclassroom.com/Class/newtlaws/u2l4a.cfm
6. Check Your Understanding 1 - Answer The forces are equal!
For every action, there is an equal reaction. The fact that the
firefly splatters only means that with its smaller mass, it is less
able to withstand the larger acceleration resulting from the
interaction.
http://www.physicsclassroom.com/Class/newtlaws/u2l4a.cfm
7. Check Your Understanding 2 A rifle recoils when it is fired
as a result of action-reaction force pairs. A gunpowder explosion
creates hot gases that expand outward allowing the rifle to push
forward on the bullet. The bullet pushes backwards upon the rifle.
The acceleration of the recoiling rifle when compared with that of
the bullet is: a. greater. b. smaller. c. the same.
http://www.physicsclassroom.com/Class/newtlaws/u2l4a.cfm
8. Check Your Understanding 2 - Answer Correct Answer: B The
force on the rifle equals the force on the bullet. Yet,
acceleration depends on both force and mass. = The bullet has a
greater acceleration due to the fact that it has a smaller mass.
http://www.physicsclassroom.com/Class/newtlaws/u2l4a.cfm