At the maximum height of a body thrown vertically up

Options

A. velocity is not zero but acceleration is zero
B. acceleration is not zero but velocity is zero
C. both acceleration and velocity are zero
D. both acceleration and velocity are not zero

Answer

To solve the question regarding the state of a body thrown vertically upwards at its maximum height, we need to analyze the concepts of velocity and acceleration.

### Step-by-Step Solution:

1. **Understanding the Motion**: When a body is thrown vertically upwards, it moves against the force of gravity until it reaches its maximum height. At this point, the body momentarily stops before it starts falling back down.

2. **Velocity at Maximum Height**: At the maximum height, the upward velocity of the body becomes zero. This is because the body has reached the peak of its trajectory and is about to reverse direction.

3. **Acceleration at Maximum Height**: Even though the body is momentarily at rest at the maximum height, the acceleration due to gravity (denoted as \( g \)) is still acting on the body. This acceleration is always directed downwards, towards the center of the Earth.

4. **Conclusion**: Based on the analysis:
- The velocity of the body at maximum height is **zero**.
- The acceleration of the body at maximum height is **not zero** (it is equal to \( g \), acting downwards).

5. **Final Answer**: Therefore, the correct option is: **Acceleration is not zero, but velocity is zero**.