A person sitting in an open car moving at constant velocity throws a ball vertically up into air. The ball falls

Options

A. Outside the car
B. In the car ahead of the person
C. In the car to the side of the person
D. Exactly in the hand which throw it up

Answer

To solve the problem of a person sitting in an open car moving at constant velocity throwing a ball vertically up into the air, we can analyze the motion step by step.

### Step-by-Step Solution:

1. **Understanding the Initial Conditions**:
- The car is moving at a constant velocity, which means that both the car and the person inside it have the same horizontal velocity, let's denote it as \( V \).

2. **Throwing the Ball**:
- When the person throws the ball vertically upwards, the ball also has the same horizontal velocity \( V \) as the car at the moment of release. Therefore, the ball has two components of motion: a vertical component (upwards) and a horizontal component (the same as the car's velocity).

3. **Vertical Motion of the Ball**:
- The vertical motion of the ball is influenced by gravity. When the ball is thrown upwards, it will rise until it reaches its maximum height, and then it will fall back down. The time taken to go up and come back down will be the same.

4. **Horizontal Motion of the Ball**:
- Since there are no horizontal forces acting on the ball (assuming air resistance is negligible), the ball will continue to move horizontally with the same velocity \( V \) as the car.

5. **Analyzing the Motion**:
- As the ball goes up and comes down, it will maintain its horizontal velocity \( V \). Therefore, while the ball is in the air, it continues to move horizontally at the same speed as the car.

6. **Conclusion**:
- When the ball falls back down, it will land back in the hand of the person who threw it because both the ball and the car are moving horizontally at the same velocity. Thus, the ball falls exactly where it was thrown from.

### Final Answer:
The ball falls back into the hand of the person who threw it.