A lawyer, a physicist and an economist are locked up together in a prison cell

A lawyer, a physicist and an economist are locked up together in a prison cell. Once a day a warden throws a can of meat through the bars - without a can opener! The lawyer says: "I'm sick of this, I'll sue the prison for inhumanity!". The physicist says: "No, let me calculate the ideal force and angle at which to throw the can against the wall, so it will crack open!"... upon which the economist says: "No, I got it, let's just assume the can is open - and we'll all have enough to eat!"