Free fall on an object in vacuum is a case of motion with

Options

A. 1. uniform velocity
B. 2. uniform acceleration
C. 3. variable acceleration
D. 4. uniform speed

Explanation

To solve the question regarding the motion of an object in free fall in a vacuum, we can break it down step by step:

### Step-by-Step Solution:

1. **Understanding Free Fall**:
- Free fall refers to the motion of an object under the influence of gravity alone. In a vacuum, there is no air resistance acting on the object.

2. **Identifying Forces**:
- In a vacuum, the only force acting on the object is the gravitational force (weight). This force causes the object to accelerate towards the Earth.

3. **Acceleration Due to Gravity**:
- The acceleration due to gravity (g) is approximately 9.81 m/s² near the surface of the Earth. This acceleration is constant for objects in free fall, as long as they are close to the Earth's surface.

4. **Uniform Acceleration**:
- Since the acceleration (g) is constant, we conclude that the object is undergoing uniform acceleration. This means that the rate of change of velocity is constant throughout the motion.

5. **Velocity Change**:
- While the acceleration is constant, the velocity of the object is not constant; it increases as the object falls. Therefore, the speed of the object changes continuously.

6. **Conclusion**:
- Based on the analysis, we can conclude that the free fall of an object in a vacuum is a case of motion with constant uniform acceleration.

### Final Answer:
The correct answer is that free fall on an object in a vacuum is a case of motion with **constant uniform acceleration**.