Calculating Minimum Ball Speed for Safe Passage through Rotating Windmill Blades

[mini_mia]

Hi! I'm not sure where to start on this question and I would be very thankful if somebody could help me on it:

At a mini golf course, a golf ball passes through a windmill. The windmill has 8 blades and rotates at an angular speed of 1.25 rad/s. The opening between successive blades is equal to the width of a blade. A golf ball of diameter 4.50 x 10^-2 m is just passing by one of the rotating blades. What must the minimum speed of the ball be so it won't be hit by the next blade?

 

[Tide]

Hint 1: How long does it take the golf ball to travel 4.5 cm at a given speed?

Hint 2: How long is the opening available for the ball to pass through?

 

[CartoonKid]

https://www.physicsforums.com/showthread.php?t=52326

You can refer to the previous post. This is the link.

 

[mini_mia]

Thank you guys for trying to help me! Now I'm going to attempt to do it. :D