Question
If a 930cm3 piston compresses the air in the cylinder to 1/8 its total volume, what is the pressure after the gas is compressed?
Answers
Devron
Not sure, but if since pressure in volume are inversely related you should see an increase in the pressure. so if volume decreased by 7/8, the pressure should increase by 7/8.
DrBob222
You don't list a pressure initially; the final pressure will be eight times (8x) the initial pressure.
Devron
Just a question, how do you get 8x the initial pressure when it decreased by 7/8?
DrBob222
p1 = some convenient number, say 2 atm.
v1 = 930 cc
p2 = ?
v2 = 930*1/8 = 116.25 cc.
p1v1 = p2v2
2*930 = p2*116.25
p2 = 2*930/116.25 = 16
16 is 8*2; p increased by a factor of 8.
If the volume is reduced to 1/2 its original volume the pressure must have been doubled.
If the volume is reduced to 1/3 its original volume the pressure must have been tripled.
If the volume is reduced to 1/10 its original volume the pressure must have been increased by 10 times (a factor of 10).
If the volume is decreased to 1/8 its original volume the pressure must have been increased by a factor of 8.
v1 = 930 cc
p2 = ?
v2 = 930*1/8 = 116.25 cc.
p1v1 = p2v2
2*930 = p2*116.25
p2 = 2*930/116.25 = 16
16 is 8*2; p increased by a factor of 8.
If the volume is reduced to 1/2 its original volume the pressure must have been doubled.
If the volume is reduced to 1/3 its original volume the pressure must have been tripled.
If the volume is reduced to 1/10 its original volume the pressure must have been increased by 10 times (a factor of 10).
If the volume is decreased to 1/8 its original volume the pressure must have been increased by a factor of 8.
Devron
Got it. Should have just done the math.