If the carrier is the held component and the ring gear is input, the result is reverse reduction.

• A. True
• B. False
• C. Only if sun gear is input
• D. Only if carrier is output

Answer: (B)

Holding the carrier fixes the planet gears, so driving the ring gear must make the sun gear rotate as the reaction path. The motion will be in the opposite direction to the ring input, but the speed is governed by the teeth counts. With typical gear counts (ring has more teeth than the sun), the sun gear speed tends to be greater in magnitude than the ring input—an amplification rather than a reduction. So describing the outcome as “reverse reduction” isn’t accurate. The result is opposite in direction, but not a guaranteed reduction in speed.