A horse pulls upon a wagon, but according to Newton’s third law the wagon pulls back with an equal and opposite force upon the horse. How then can either the wagon or the horse move?
I'm supposed to draw a free body diagram but I'm not sure on the forces.?
I have
<<<<< Force on the horse by the wagon
>>>>> Force on Hourse by road
>>>>> Force on wagon by horse
the body moves because the horse applies a force to it that is not balanced. The force the body exerts on the horse is not counted as a force on the body.
To understand how the horse and the wagon can move despite the equal and opposite forces, let's break down the forces involved using a free body diagram.
A free body diagram is a visual representation that shows all the forces acting on an object. In this case, we'll draw separate diagrams for both the horse and the wagon.
Free Body Diagram for the Horse:
1. <<<<< Force on the horse by the wagon: This represents the force exerted on the horse by the wagon. According to Newton's third law, this force is equal in magnitude but opposite in direction to the force exerted on the wagon by the horse.
2. >>>>> Force on the horse by road: This represents the force exerted on the horse by the road. It acts in the forward direction, providing the necessary traction for the horse to pull the wagon.
Free Body Diagram for the Wagon:
1. >>>>> Force on wagon by horse: This represents the force exerted on the wagon by the horse. As mentioned earlier, this force is equal in magnitude but opposite in direction to the force exerted on the horse by the wagon.
Now, let's examine the motion of the horse and the wagon:
When the horse pulls on the wagon, it exerts a force that propels the wagon forward. This force is transmitted through the wagon's wheels to the ground, creating a reaction force in the opposite direction (>>>>> Force on the horse by road). This reaction force allows the horse to move forward.
At the same time, the wagon exerts an equal and opposite force on the horse (<<<<< Force on the horse by the wagon). This force does not prevent the horse from moving forward because it only opposes the force exerted on the wagon by the horse.
In summary, the motion of both the horse and the wagon is possible due to the presence of external forces such as the force exerted on the horse by the road, which provides the necessary traction for the horse to pull the wagon.