The person pushing the water backwards is the action force. The water pushing the person foward is the reaction force.
Newton's Third Law of Motion
Science Page
| Newton’s 3rd Law states that when one object pushes against another object, the other object pushes back with an equal force in an opposite direction. | Newton explains that when two objects exert a force on each other they interact. If you push on a table, the table will push back on you. These two forces are called reaction and action forces. A force is a push or a pull upon an object. They will always be in pairs like all forces. The reaction force has the same magnitude but is going in the opposite direction. Newton’s 2nd Law helps to understand this better. This law states that the acceleration produces by a net force on a body is directly proportional to the magnitude of the net force, is in the same direction as the net force, and is inversely proportional to the mass of the body. Net Force is the combination of all forces acting upon an object. Acceleration is the rate at which velocity changes. |
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In the picture to the right, interaction is occurring between the forces. The exhausts flow that is being pushed backwards out of the engine is the action force. The engine being pushed forward is then the reaction force. This is a great example of interaction. |
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While the box is sitting on the table, it is actually pushing down on the table. This is the action force. But the table is also pushing up on the box. This becomes the reaction force. |
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The person pushing the water backwards is the action force. The water pushing the person foward is the reaction force. |
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The skateboard is being pushed backwards by the foot, this is the action force. The foot being pushed forward by the skateboard is the reaction force. |