When a horse pulls a cart, the force which is responsible for the movement of cart is

Options

A. the force of the horse on the cart
B. the force of the ground on the horse
C. the force of the ground on the cart
D. the force of the horse on the ground.

Explanation

To solve the question "When a horse pulls a cart, the force which is responsible for the movement of the cart is," we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Forces Involved**: When a horse pulls a cart, there are several forces at play. The horse exerts a force on the ground with its hooves, and the ground exerts an equal and opposite force back on the horse.

2. **Understand Newton's Third Law**: According to Newton's Third Law of Motion, for every action, there is an equal and opposite reaction. This means that when the horse pushes down on the ground, the ground pushes back up on the horse with an equal force.

3. **Determine the Movement Mechanism**: The horse uses its legs to push against the ground. The force exerted by the ground on the horse allows the horse to move forward. As the horse moves forward, it pulls the cart along with it due to the connection between the horse and the cart (usually through a harness or rope).

4. **Identify the Correct Force**: The question asks which force is responsible for the movement of the cart. Since the horse's movement is facilitated by the force exerted by the ground on the horse, this force is what ultimately causes the cart to move forward.

5. **Select the Correct Answer**: Based on the analysis, the correct answer is the force of the ground on the horse (Option 2). This force enables the horse to move forward, which in turn pulls the cart.

### Final Answer:
The force responsible for the movement of the cart is **the force of the ground on the horse**.

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