When a horse pulls a wagon, the force that causes the horse to move forward is the force

Options

A. He exerts on the wagon
B. The wagon exerts on him
C. The ground exerts on him
D. He exerts on the ground

Explanation

To solve the question regarding the force that causes the horse to move forward when it pulls a wagon, we can break it down step by step:

### Step-by-Step Solution:

1. **Identify the System**: We have a horse and a wagon. The horse is pulling the wagon forward.

2. **Understand the Forces Involved**:
- The horse exerts a force on the wagon in the forward direction.
- According to Newton's Third Law of Motion, for every action, there is an equal and opposite reaction. Therefore, the wagon exerts an equal force back on the horse in the opposite direction.

3. **Consider the Ground Reaction**:
- The horse stands on the ground and exerts a downward force on the ground due to its weight.
- The ground exerts an upward normal force on the horse, which is equal to the weight of the horse.

4. **Frictional Force**:
- The ground also exerts a frictional force on the horse in the forward direction when the horse pushes backward against the ground. This frictional force is what allows the horse to move forward.

5. **Conclusion**:
- The force that causes the horse to move forward is the frictional force exerted by the ground on the horse. This force acts in the forward direction, enabling the horse to pull the wagon.

### Final Answer:
The force that causes the horse to move forward is the force exerted by the ground on the horse in the forward direction.

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