$$1 - P,\,\,2 - R,\,\,3 - Q,\,\,4 - S$$

$$1 - P,\,\,2 - R,\,\,3 - S,\,\,4 - Q$$

$$1 - S,\,\,2 - Q,\,\,3 - P,\,\,4 - R$$

$$1 - S,\,\,2 - R,\,\,3 - P,\,\,4 - Q$$

$$5.2$$

$$4.2$$

$$3.2$$

$$2.2$$

$${{Volume\,\,of\,\,wheel\,\,wear} \over {Volume\,\,of\,\,work\,\,material\,\,removed}}$$

$${{Volume\,\,of\,\,work\,\,material\,\,removed} \over {Volume\,\,of\,\,wheel\,\,wear}}$$

$${{Cutting\,\,speed} \over {feed}}$$

$${{longitudinal\,\,feed} \over {transverse\,\,feed}}$$

graphite

tungsten

nickel

cobalt