Question

Choose the correct option.
Company Z operates an aerospace machinery that uses two types of ball bearing -
A and B. What is the ratio of life of bearing A to the life of bearing B?
Given that the two bearings operate at loads of 27N and 45N respectively

A 125/27
B 25/9
C 27/125
D 5/3​

Answer 1

Given :

Bearing, A operates at 27N

Bearing, B operates at 45N

To Find:

We have to find the ratio of life of bearing A to the life of bearing B.

Solution:

Rating life is the life of bearing calculated for 90% reliability.

The basic formula for calculating the life of a bearing is:

where:

C is the dynamic capacity

P is the equivalent bearing load

N is the rotating speed in RPM

e =3 for ball bearing and 10/3 for roller bearings

We have to find,

∴ The ratio of the life of bearing A to the life of bearing B is

Hence, option A is correct.