- #1
johncena
- 131
- 1
I can't understand the significance of Newton's third law.
What would happen if there were no reaction forces?
What would happen if there were no reaction forces?
Is it not true that the wall is not moving because of frictional force between wall and the ground?dacruick said:Then Newton's Third Law would probably be "every force has no equal or opposite reaction force". but what is your question really. The significance to me of Newton's third law is that force is a kind of conservative value. It kind of governs motion. When you apply force to a wall, why doesn't the wall have an acceleration according to F=ma? Well that is because the wall is also applying the same force in the opposite direction, counter-acting your force. If there was no reaction force, the wall would have to move will acceleration F/m. I feel like I may not be answering your question though, would you like to be more specific?
bp_psy said:Nothing would happen because there would be absolutely NO forces.
Newtons three laws represent among other things a definition of force Couples. In the interaction of objects what arises is a force couple which is a thing in itself that is composed by 2 force vectors each acting on one of the 2 objects in the interaction.When doing problems it is sometimes useful to ignore one of the members of the couple but usually neglecting the other member is the mistake made most often.When thinking about the nature of the laws, thinking about only one member of the force is not useful and ultimately meaningless. What the interaction has created is the couple. If the interaction had not happened neither of the components would exist.And to this point no interaction has been observed that only created half a force couple. So the conclusion if the third law was not true then no forces would exist. This is my logic and there are probably more convincing and rigorous arguments out there.johncena said:Why no forces? I mean , what would happen if there is only action force,no reaction?
Your question has no answer.johncena said:I can't understand the significance of Newton's third law.
What would happen if there were no reaction forces?
Newton's Third Law states that for every action, there is an equal and opposite reaction. This means that when an object exerts a force on another object, the second object will exert an equal force in the opposite direction on the first object.
Some examples of Newton's Third Law include: a person pushing against a wall (the person exerts a force on the wall, and the wall exerts an equal force back on the person), a rocket launching into space (the rocket's engines push against the ground, and the ground pushes back with an equal force, propelling the rocket forward), and a balloon being inflated (the air inside the balloon exerts a force on the walls of the balloon, and the walls of the balloon exert an equal force back, causing the balloon to expand).
Newton's Third Law is closely related to the conservation of momentum, which states that the total momentum of a system remains constant in the absence of external forces. When two objects interact with each other, their momenta will always be equal and opposite due to Newton's Third Law. This means that the total momentum of the system is conserved.
Newton's Third Law is significant because it is one of the fundamental laws of physics and is essential for understanding the motion of objects. It helps explain why objects move and how forces interact with each other. This law is also crucial in fields such as engineering, aeronautics, and space exploration.
No, there are no exceptions to Newton's Third Law. It applies to all objects and all interactions, whether they are on a large or small scale. However, it may seem like there are exceptions in some cases, such as a person jumping on a trampoline (the trampoline exerts a greater force on the person, causing them to bounce higher), but this is due to other forces at play, such as gravity and the elasticity of the trampoline material.