PHY HELP ???

[niassu]

question no,2c ni may 1997

 

[haochen]

question no,2c ni may 1997

i think by:
calculate 30% of 0.15 =0.045
the do cross mutiplication
so
(0.045 * 5.0x10^5 ) / 0.15
=1.5x10^5 Pa

hope it is correct

 

[niassu]

well thnx its right but the prloblem is that i donot understand how to get it :unknown:
sorry for annyoing but why did u got the final volume 0.15 and the initial 0.045 wasn't the initial 0.15 or what really wanna an expalntion plz :sorry:

 

[unplugged]

It's actually simpler than that. Reducing the mass equates to reducing the pressure by the same percentage. so you got 5 x 10^5 , you know the mass is reduced by 70% so the pressure is reduced by 70%.
5 x 30/100 = 1.5 x 10^5

Think of it like this , pressure is about how many particles hitting the borders of the container each second. So if you reduce the amount of particles by 70% , you get 70% less particles hitting the walls of the container every second , so you get 70% less pressure.