# Need Help on Physic Homework

noobies
1st of all please give me some guidance since I am a new here and please remind me if I am do wrong in term of my wrongly area of posting, i just want to make some freinds and to share the knowledge wif all of u guys, thanks for supporting and thanks for all ur help and guide

thanks agains

## Homework Statement

http://img216.imageshack.us/img216/20/22129520.png [Broken]

i need ur help regarding this, I've tried by my self but I am soo sure that I've done wrongly

here it comes
the figure shows that how i oversizing the hex 1/2" nut by oversizing machine. the pressure which is 3.5kg/mm sq is push the nut thru the tapper of a 100 mm length. how can i determine the time taken,t for the nut to going thru the 100mm tapper

here is the detail that may required

size of nut: 1/2 inch hexagonal 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 = ?

i

## Homework Equations

when I am try to solve the problem, I am using this equation
1. P=Fa (find F)
2. W=F x S (find W) work = f x s
3. P= W/ t (find t) power = w/t

## The Attempt at a Solution

ive once try to determine the force exist by P=F/A:
then once i get the F, I've determine the work done by W=F x S;
lastly I've tried to find the time,t by using P= W/t which is P is a power of machine while W is a work done

but I am not satisfied with the answer that i got,

here is my work

1st. To find area of 1/2” inch hex nut (im not sure if it is correct)

area of hex nut?? = 6as + Ph
= 6(2)(1.2) + 7.2 (1.1)
= 22.32cm

wheres a= apothem length
s= side length
perimeter of the base= 6 * s
= 6 * (1.2)
= 7.2

2nd. Find Force, F

(converting 3.5kg/mm sq into unit pascal I got 34.3MPa)

P=F/A
F=PA
=34.3Mpa * (22.32 x 10-2)

F= 7.66 x 106 N

3rd. Det work done

W = F * S
= 7.66 x 106 (100 x 10-3)

W= 765.6 x 103 N

4th find time, t

P=W/t
t=W/P

where p= power of machine =5HP = 3730 watt ?

t=765.6 x 103 N / 3730

final answer; t=205 sec ?

can anybody correct me if I am wrong or giving me for some tips or correct formula on how to done iti would very great of any possible idea and i'll tried by myself before refer to all of u back

if u hv any question or didnt understand wif the question, please ask me and i would really great to explain

thanks again

regards

Last edited by a moderator:

## Answers and Replies

noobies
is it i need to consider such as angular velocity or torque or anything that i misconsidered?

noobies
thanks 4 those who r viewing my thread, i still hv no idea wif this question except for my trial solution, any idea would be please

noobies
still hv no idea mates?
im might be offline for a while and i'll update any of ur question (if have) later and i will because this is quite important to me

thanks mate

noobies
anybody?need ur favor and thanks

p/s:if I am done it in wrong section or maybe my way is a bit annoying pls to let me know as i can manage myself to do it rite

noobies

noobies
can i know why am i didnt get any reply?
is it I am do it in wrong way?