Topic: Machine Design
Life of a ball bearing at a load of 10 kN is 24000 hours. If the load is increased to 20 kN (all other conditions are same), its life in hour is
- A. 1000 h
- B. 3000 h
- C. 6000 h
- D. 12000 h
Answer: B. 3000 h
Explanation: Life L = (C/P)^n. For ball bearing n = 3, so L is proportional to 1/P³. L2/L1 = (P1/P2)^3. L2 = 24000 * (10/20)^3 = 24000 * (1/8) = 3000 hours.