A player throws a ball vertically upwards with velocity u. At highest point,

Options

A. both the velocity and acceleration of the ball are zero.
B. the velocity of the ball is u but its acceleration
C. the velocity of the ball is zero but its acceleration is g.
D. the velocity of the ball is u but its acceleration is g.

Explanation

To solve the problem, we need to analyze the motion of the ball when it reaches the highest point after being thrown vertically upwards with an initial velocity \( u \).

### Step-by-Step Solution:

1. **Understanding the Motion**: When the ball is thrown upwards, it moves against the force of gravity. As it rises, its velocity decreases due to the acceleration caused by gravity acting in the opposite direction.

2. **At the Highest Point**: At the highest point of its trajectory, the ball momentarily comes to rest before it starts falling back down. This means that the velocity of the ball at this point is \( 0 \, \text{m/s} \).

3. **Acceleration at the Highest Point**: Even though the velocity is \( 0 \) at the highest point, the ball is still under the influence of gravity. The acceleration due to gravity \( g \) is acting downwards throughout the motion, including at the highest point. Therefore, the acceleration of the ball at the highest point is \( g \).

4. **Conclusion**: Hence, at the highest point:
- The velocity \( v = 0 \, \text{m/s} \)
- The acceleration \( a = g \)

### Final Answer:
At the highest point, the velocity of the ball is \( 0 \, \text{m/s} \) and the acceleration is \( g \).

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