With 40 psi a 5 inch cylinder how much force is on a 375 inch tip?

Answer 1

5 inch diameter cylinder --> pi * radius^2 --> pi * 5^2 = 78.54 inches squared.

40 psi --> 40 lbf/in2 * 78.54 in2 = 3141.59 lbf

The force on the tip is about 3141.6 lbf, regardless of how large it is.

If you want FORCE PER AREA, then, assuming the tip is circular and flat against whatever is contacting the tip surface, and also assuming you mean 0.375 inches and not 375 inches:

Force/Area --> 3141.6lbf / (pi * 0.375^2) = 284.4 ksi (284,400 psi)

That's a lot of force.