please help, some basic physic formulae i think

i need ur help regarding this, ive tryed by my self but im soo sure that ive done wrongly

here it comes

the figure shows that how i oversizing the hex 1/2" nut by oversizing machine. the pressure which is3.5kg/mm sqis pushes the nut thru the tapper of a100 mm length. how can i determine thetime taken,tfor the nut to going thru the 100mm tapper

here is the detail that may required

size of nut:1/2 inchhexagonal nut (internal dia of nut = 1/2 inch)

pressure, P:3.5kg/mm sq

tapper length,L:100mm

Power of machine:5HP

Speed:750 rpm

time,t= ???

ive once try to determine the force exist byP=F/A:

then once i get theF, ive determine the work done which isW=F x S;

lastly ive tried to find the time,tby usingP= W/twhich isPis a power of machine whileWis a work done

but im not satisfied with the answer that i got,

can anybody correct me if im wrong or giving me for some tips or correct formulae on how to done it

i would be greatly thanks

regards

noob