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 B — reducing the quantity of lubricant until only a mist of oil is present on the ball bearings

Excessive grease or oil in high-speed ball bearings causes severe internal fluid friction and churning, rapidly escalating temperatures and leading to lubricant breakdown. Maintaining the correct minimal lubricant level ensures boundary or mist lubrication without thermal overload.