The pressure inside a champagne bottle is 5.4 atm higher than the air pressure outside. The neck of the bottle has an inner radius of 0.9cm. What is the frictional force on the cork due to the neck of the bottle? I used the equation F=A*P, but I'm getting 137.41N and that's not right. I think I'm doing something wrong with the air pressure outside. How do I set this problem up?