To get the maximum flight a ball must be thrown as :

Options

A.
B.
C.
D.

Explanation

To determine how to achieve maximum flight for a ball when thrown, we can analyze the effects of velocity and spin on the ball's trajectory using Bernoulli's principle. Here’s a step-by-step solution:

### Step 1: Understand the Concept of Bernoulli's Principle
Bernoulli's principle states that in a fluid flow, an increase in the fluid's velocity occurs simultaneously with a decrease in pressure. This principle will help us analyze the effects of different throwing techniques on the ball's flight.

**Hint:** Recall that Bernoulli's equation relates pressure and velocity in fluid dynamics.

### Step 2: Analyze the Options Given
We have four options regarding how to throw the ball:
1. Forward velocity with clockwise spin.
2. Forward velocity with anti-clockwise spin.
3. Only forward velocity.
4. Any of these methods could yield the same result.

**Hint:** Consider how the direction of spin affects the velocity distribution around the ball.

### Step 3: Evaluate Option A (Clockwise Spin)
When the ball is thrown with a forward velocity and a clockwise spin:
- The upper surface of the ball has a velocity of \( V - R\omega \) (where \( R \) is the radius and \( \omega \) is the angular velocity).
- The lower surface has a velocity of \( V + R\omega \).
- This results in higher pressure on the top and lower pressure on the bottom, creating a net downward force.

**Hint:** Think about how the pressure differences affect the ball's flight.

### Step 4: Evaluate Option B (Anti-clockwise Spin)
When the ball is thrown with a forward velocity and an anti-clockwise spin:
- The upper surface has a velocity of \( V + R\omega \).
- The lower surface has a velocity of \( V - R\omega \).
- This results in lower pressure on the top and higher pressure on the bottom, creating a net upward force.

**Hint:** Consider how the upward force could enhance the ball's flight.

### Step 5: Evaluate Option C (Only Forward Velocity)
If the ball is thrown with only forward velocity, there are no pressure differences created by spin. The pressures above and below the ball remain equal, resulting in no net force acting on the ball.

**Hint:** Reflect on how the absence of spin affects the pressure distribution.

### Step 6: Conclusion
From the analysis:
- Option A results in a net downward force, reducing flight.
- Option B results in a net upward force, enhancing flight.
- Option C provides no net force.

Thus, the best method to achieve maximum flight for the ball is to throw it with a forward velocity and an anti-clockwise spin (Option B).

**Final Answer:** To achieve maximum flight, the ball must be thrown with a forward velocity and an anti-clockwise spin (Option B).