In life, we often find that when we play with rubber bands in the state of being stretched, our hands are also using force, while the longer we pull the more we feel the strain. This is what we will explain today the interaction of forces – the action and reaction forces.
The Concept of Force Interaction
The interaction of forces is one of the basic concepts of physics and is the external expression of many physical laws. It is the concept that the action of forces is mutual, an object exerting force on another object at the same time, the object is also subject to the force from each other. That is, the role of force between objects is mutual, the object applying the force is also the object receiving the force. As shown in the figure below, a person will go ashore while the boat will float away backward, because the person gives a force, the force makes the boat float away backward, and the boat will also give a reaction force to the person, making the person move forward.
Note:
1.Force interaction is a relationship between an object and another object.
The relationship between an object and another object is divided into two categories, the relationship of force, the relationship of relative position. Where the relationship of forces will (but not necessarily) affect the state of motion of another object. The relative position relationship will not affect another object.
2. Force interaction is a form of energy expression, such as potential energy, mass, acceleration, etc.
3. Force interaction is a way of energy conversion, such as the thrust of gunpowder to convert the chemical energy of gunpowder into the kinetic energy of the bullet head.
4.In relativity theory, force is a reflection of space curvature.
The concept of action and reaction forces
The action of forces between objects is mutual, and the two forces interacting with each other are the action and reaction forces.
Understanding of Force Interaction
1. The action and reaction forces always appear in pairs. They arise, change and disappear at the same time, there is no sequence
2. The action and reaction forces on two different objects, each producing its own effect, will never cancel
3. The action and reaction forces are forces of the same nature.
4. The interaction force between objects can be either a contact force or a “field” force
5. An object exerts a force on another object in two ways, one is the direct (contact) action by the object, and the other is the indirect (non-contact) action between objects.
6. The action of forces between objects is mutual, the object applying the force and the object receiving the force at the same time.
- Characteristics of interacting forces
- Opposite direction
- Equal in size
- Acting in the same line
- Acting on different objects
- Generate, disappear, increase and decrease at the same time
Through the above explanation, our students should be clear that the interaction of forces is actually a mutual force between objects, and this force exists and disappears at the same time.
Examples of Interactive Forces
Shoot a basketball with your hand, hand to basketball force basketball hand also apply force, the hand will feel pain.
On the skating surface with the hand to push the wall, people will slide backward.
Electric lights hanging from the ceiling, the lights are subject to the upward pull of the ceiling, and the ceiling is subject to the downward pull of the lights.
When a rocket lifts off and jets downward, the gas ejected has an upward reaction force on the rocket.
The human foot acts backward on the road surface, and the road surface has a reaction force forward on the human foot.
The kicking foot is subjected to a force, and the ball is subjected to our force to fly out.
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