Answer:
See explaination
Step-by-step explanation:
From the following,(see attachment) we have the values of factor of safety for both cases
coming to primary mode of failure will be the one with a lower factor of safety which is bending
We have taken the preliminary design approach as we don't have enough data and a quality standard of 6 for pinion is provided to distract us to go for final design approach.
But as we are not aware about the quality standard for gear, face width, power, etc so it is not possible to go with final design approach