An outer hub rotates around a stationary shaft, supported by two tapered roller bearings as shown in Fig. 11–23. The device is to operate at 250 rev/min, 8 hours per day, 5 days per week, for 5 years,...

shown in Fig. 11–23. The device is to operate at 250 rev/min, 8 hours per day, 5 days per week,

for 5 years, before bearing replacement is necessary. A reliability of 90 percent on each bearing

is acceptable. A free body analysis determines the radial force carried by the upper bearing

to be 12 kN and the radial force at the lower bearing to be 25 kN. In addition, the outer

hub applies a downward force of 5 kN. Assuming bearings are available with
K
= 1.5, find

the required radial rating for each bearing. Assume an application factor of 1.2.