A collector with what characteristic increases velocity at higher speeds?

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

Answer: (D)

The key idea is how rotation creates tangential speed. For any rotating component, the linear (tangential) velocity at its outer edge is v = ωr, where ω is the angular speed and r is the radius. Keeping ω the same, increasing the radius (i.e., the diameter) directly increases the edge velocity. So a collector with a larger diameter will have a higher velocity at the outer edge when the system spins, especially as speed climbs. The other options don’t raise the tangential velocity in the same way: a smaller diameter reduces edge velocity, a shorter length doesn’t change the outer-edge speed, and “merge” isn’t a geometric factor that increases edge velocity.