A body is projected vertically upward direction from the surface of earth. If upward direction is taken as positive, then acceleration of body during its upward and downward journey are respectively

Options

A. Positive, negative
B. Negative, negative
C. Positive, positive
D. Negative, positive

Answer

To solve the question regarding the acceleration of a body projected vertically upward and its behavior during its upward and downward journey, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Motion**:
- When a body is projected vertically upward, it moves against the force of gravity.

2. **Identifying the Direction of Acceleration**:
- The only force acting on the body during its motion (both upward and downward) is the gravitational force, which acts downward towards the center of the Earth.

3. **Acceleration During Upward Motion**:
- As the body moves upward, it experiences a deceleration due to gravity. The acceleration due to gravity (g) acts downward, which we take as negative in our coordinate system where upward is positive.
- Therefore, the acceleration during the upward journey is \( -g \) (where \( g \approx 9.81 \, \text{m/s}^2 \)).

4. **Acceleration During Downward Motion**:
- Once the body reaches its highest point, it starts to fall back down. During this downward journey, the gravitational force still acts downward.
- Thus, the acceleration during the downward journey is also \( -g \).

5. **Conclusion**:
- The acceleration of the body during its upward journey is \( -g \) and during its downward journey is also \( -g \).

### Final Answer:
- The acceleration of the body during its upward and downward journey is respectively \( -g \) and \( -g \).

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