An object thrown into space horizontally under the action of earth's gravity is called a

Options

A. projectile
B. trajectory
C. spaceship
D. none of these

Answer

To solve the question "An object thrown into space horizontally under the action of Earth's gravity is called a," we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Motion**:
- When an object is thrown horizontally, it has an initial velocity in the horizontal direction. This velocity is denoted as \( u_x \).
- At the same time, the object is subjected to the force of gravity, which acts downward. This force causes the object to accelerate downwards.

2. **Identifying the Axes**:
- We can define the horizontal direction as the x-axis and the vertical direction (downward) as the y-axis.
- The object will have two components of motion: horizontal motion (constant velocity) and vertical motion (accelerated due to gravity).

3. **Analyzing the Vertical Motion**:
- Initially, when the object is thrown, its vertical velocity \( v_y \) is zero.
- As the object moves, it gains downward velocity due to the acceleration caused by gravity, which is denoted as \( g \).

4. **Understanding the Resultant Motion**:
- The object will follow a curved path due to the combination of its constant horizontal velocity and the increasing vertical velocity.
- This type of motion is characterized by having two velocities acting simultaneously: one in the horizontal direction and one in the vertical direction.

5. **Defining the Type of Motion**:
- The motion described, where an object is thrown and moves under the influence of gravity while maintaining a horizontal component, is known as **projectile motion**.
- The path traced by the object during this motion is called a **trajectory**.

6. **Conclusion**:
- Therefore, the answer to the question is that an object thrown into space horizontally under the action of Earth's gravity is called **projectile motion**.

### Final Answer:
**Projectile Motion**