A stone is released from a rising balloon accelerating upward with acceleration a. The acceleration of the stone just after the release is

Options

A. a upward
B. g downward
C. `(g-a)` downward
D. `(g+a)` downward

Explanation

To solve the problem of determining the acceleration of a stone just after it is released from a rising balloon that is accelerating upward with acceleration \( a \), we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Initial Conditions**:
- The balloon is rising with an upward acceleration \( a \).
- While the stone is inside the balloon, it moves with the same acceleration \( a \) as the balloon.

**Hint**: Recognize that objects inside a moving reference frame (like the balloon) share the same motion as that frame.

2. **Release of the Stone**:
- When the stone is released, it is no longer in contact with the balloon. At the moment of release, the stone has the same upward velocity as the balloon.

**Hint**: Consider the concept of inertia; the stone will continue moving in the direction it was last moving at the moment of release.

3. **Forces Acting on the Stone After Release**:
- After the stone is released, the only force acting on it is the gravitational force, which acts downward. This force is equal to \( mg \), where \( m \) is the mass of the stone and \( g \) is the acceleration due to gravity.

**Hint**: Identify the forces acting on the object after it is released to determine its motion.

4. **Determine the Acceleration of the Stone**:
- Since the only force acting on the stone after it is released is the gravitational force, the acceleration of the stone will be equal to \( g \) downward.
- Therefore, the acceleration of the stone just after release is \( g \) downward.

**Hint**: Remember that the acceleration of an object is determined by the net force acting on it divided by its mass (Newton's second law).

5. **Conclusion**:
- The acceleration of the stone just after it is released from the balloon is \( g \) downward, regardless of the upward acceleration \( a \) of the balloon.

### Final Answer:
The acceleration of the stone just after release is \( g \) downward.

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