consider the acceleration velocity and displacement of a tennis ball as it falls to the ground and bouces back. Derections of which of these changes in the process

Options

A. velocity only
B. displacement and velocity
C. acceleration, velocity and displacement
D. displacement and acceleration

Explanation

To analyze the motion of a tennis ball as it falls to the ground and bounces back, we will consider the acceleration, velocity, and displacement at different stages of its motion.

### Step 1: Analyze the falling motion
- When the tennis ball is falling towards the ground:
- **Acceleration (a)**: The acceleration due to gravity acts downwards, so \( a = g \) (approximately \( 9.81 \, \text{m/s}^2 \)).
- **Velocity (v)**: The velocity of the ball is also directed downwards as it falls, so \( v < 0 \) (if we take downward as negative).
- **Displacement (s)**: The displacement of the ball is in the downward direction as it moves towards the ground, so \( s < 0 \).

### Step 2: Analyze the bouncing motion
- After the ball hits the ground and bounces back:
- **Acceleration (a)**: The acceleration due to gravity still acts downwards, so \( a = g \) (still directed downwards).
- **Velocity (v)**: As the ball bounces back up, the velocity is now directed upwards, so \( v > 0 \) (if we take upward as positive).
- **Displacement (s)**: The displacement during the bounce is also directed upwards as the ball moves away from the ground, so \( s > 0 \).

### Step 3: Determine changes in direction
- **Acceleration**: The direction of acceleration does not change; it remains directed downwards throughout the entire motion.
- **Velocity**: The direction of velocity changes from downward (negative) while falling to upward (positive) while bouncing back.
- **Displacement**: The direction of displacement also changes from downward (negative) while falling to upward (positive) while bouncing back.

### Conclusion
In summary, during the entire process:
- The acceleration remains directed downwards.
- The velocity changes direction from downward to upward.
- The displacement also changes direction from downward to upward.

Thus, the correct answer is that both the velocity and the displacement change their direction during the process.