When a truck pulls a trailer, the trailer and truck accelerate forward even though the action and reaction forces are the same size but are going in opposite directions. Why don't these forces balance each other out?
DANG
The reason why the forces don't balance each other out even though they are equal in size is because they act on different objects and have different effects.
According to Newton's third law of motion, for every action, there is an equal and opposite reaction. When the truck pulls the trailer, the action force is exerted by the truck on the trailer. In response, the trailer exerts an equal but opposite reaction force on the truck.
Now, although these forces are equal in magnitude, they act on different bodies - the action force acts on the trailer, while the reaction force acts on the truck. As a result, these forces produce different accelerations on the objects.
The truck, being more massive than the trailer, experiences a smaller acceleration due to the reaction force. On the other hand, the trailer, being less massive, experiences a greater acceleration due to the action force. This causes the trailer to move forward, even though the forces involved are equal in magnitude and opposite in direction.
In summary, while the forces are indeed balanced in accordance with Newton's third law, the different masses of the truck and trailer result in different accelerations, causing the trailer to accelerate forward while the truck experiences a smaller acceleration.
According to Newton's third law of motion, for every action, there is an equal and opposite reaction. In the case of a truck pulling a trailer, when the truck exerts a force on the trailer, the trailer exerts an equal and opposite force on the truck. However, it might appear contradictory that the truck and trailer accelerate forward instead of canceling each other out. This can be explained by considering the individual forces acting on each object.
When the truck exerts a force on the trailer, it causes the trailer to accelerate forward. At the same time, the trailer exerts an equal and opposite force on the truck, which tends to push the truck backward. These forces are essentially an interaction between two separate objects, and they act on different masses (the truck and the trailer). Thus, the resulting acceleration experienced by each object depends on their respective masses.
Since the truck is usually heavier than the trailer, the force exerted by the trailer on the truck causes a relatively smaller acceleration compared to the force exerted by the truck on the trailer. The truck's forward acceleration is greater than the backward acceleration, resulting in a net forward acceleration for the truck and the trailer combined.
In simple terms, the truck's stronger force overcomes the weaker force exerted by the trailer, leading to a net force in the forward direction, causing acceleration. This is why the forces do not balance each other out, and the truck and trailer accelerate forward when the truck pulls the trailer.