finding force using volume and psi HELP!!!

[kydavies]

all you need to know is that potato is gone!

[jimmy101]

1.5 diameter barrel potato mass=.25kg

The mass seems way too high. I would WAG the spud at less than 0.10Kg and perhaps as little as 0.05Kg depending on if you use the full spud or a half spud.

Changing the mass will change the muzzle velocity estimate by the square root of the two masses. So if the spud is actually 0.1Kg instead of 0.25Kg then the expected muzzle velocity is scaled by SQRT(0.25/0.10)=1.6