Topic: Machine Design
If the load acting on the ball bearing is increased 2 times its life will
- A. Reduce by 2 times
- B. Reduce by 4 times
- C. Reduce by 8 times
- D. Not change
Answer: C. Reduce by 8 times
Explanation: The life of a ball bearing $L_{10}$ in millions of revolutions is proportional to $(C/P)^3$, where $P$ is the equivalent load. If the load is doubled (becomes $2P$), the new life is proportional to $1/(2P)^3 = 1/(8P^3)$. Therefore, the life is reduced by a factor of 8.