Question

What is the relation between rate of wear and contact surface area?

(a) Rate of wear is inversely proportional to the contact surface area

(b) Rate of wear is directly proportional to the contact surface area

(c) Rate of wear is inversely proportional to the square of contact surface area

(d) Rate of wear is directly proportional to the square of contact surface area

The question was asked in an interview for job.

The above asked question is from Meaning of Surface Texture in division Measurement of Surface Finish of Engineering Metrology

Answer 1

The correct answer is (b) Rate of wear is directly proportional to the contact surface area

To explain I would say: If any surface has large number of irregularities i.e. hills and valley then the surface will obtain good bearing properties. Rate of wear is proportional to the load per unit area and surface area in contact.