High-speed, multi-cylinder, diesel engines commonly use counterweights placed opposite to the crankpins to __________.

Correct Answer: Option B — provide dynamic balance by equalizing centrifugal force

Counterweights installed opposite to crankpins on high-speed diesel engine crankshafts supply dynamic balance by generating centrifugal forces that offset the rotating mass of the crankpins and connecting rod journals, thereby mitigating excessive main bearing loads and vibration.