An airtight box, having a lid of area 80.0 cm^2, is partially evacuated. Atmospheric pressure is 1.01 ´ 10^5 Pa. A force of 108 lb is required to pull the lid off the box. The pressure in the box was:

Question

irishboy123 · Answer

$F = A .\Delta P$

anonymous · Answer

F = 108 lb ?
A = 80cm^2 
F/A = P ??

anonymous · Answer

tried convert 108 lb to N

anonymous · Answer

I got 408.480 N

anonymous · Answer

then I divide it by 80 cm^2

anonymous · Answer

I got 480.408/80 = 6.0051

anonymous · Answer

Idk if this is right pls help

irishboy123 · Answer

http://www.wolframalpha.com/input/?i=solve%3A++%281.01+*+10%5E5%29+-+480.58%2F%2880+*+10%5E%28-4%29%29+ be careful with units :p victorian units to modern metric and cm to m

anonymous · Answer

May I ask how did you come up with 80/10^4 ?

anonymous · Answer

that will my last q
thankyouuu btw

irishboy123 · Answer

$1m = 100cm$

$.01m = 1cm$

$(.01m)^2 = (1cm)^2$

anonymous · Answer

so after that I'll use the Pgauge = Ptotal - Patmospheric ? sorry just clearing things up

irishboy123 · Answer

sounds  good!!

as long as you are happy with it too :-))  

ie getting the same answer.