Which option increases velocity at very high speeds by diameter?

• A. Larger Diameter
• B. Smaller Diameter
• C. Shorter Length
• D. Merge

Answer: (A)

When something spins, the speed of a point on its edge grows with how far that point is from the center, for a given spinning rate. This is described by v = ωr, where ω is the angular velocity and r is the radius (half of the diameter). If you keep the rotation rate the same, increasing the diameter means a larger radius, so the edge travels a longer distance per revolution and its linear speed rises. That’s why a larger diameter produces higher edge velocity at very high speeds. The other ideas don’t raise edge speed: reducing diameter lowers the edge speed, and changing length or unrelated terms wouldn’t increase the tangential velocity at the rim.