As the speed of an oil lubricated ball bearing increases, fluid friction, due to churning, generates heat. This condition may be avoided by __________.

Correct Answer: Option A — reducing the quantity of lubricant until only a mist of oil is present on the ball bearings

High-speed ball bearings require minimal lubrication to prevent churning losses. Maintaining an oil mist or a very thin film ensures adequate lubrication and cooling without the excessive drag and heat generation associated with submerging the rolling elements in a deep oil bath.