I need to calculate shear force of hook and loop. The velcro must break apart just under (but close to) 22 Newtons (approx 5 lbs). What is the surface area rqd? I am not a mathematician.

Do you have a number in mind for the ultimate shear strength (release) of the velcro. This site claims a 10 - 15 lbf/in^2 so i'll use the average for example. Area = Force/Shear so Area = 5 lbf/ 12.5 lb/in^2; Area = 0.4 in^2 so a square piece 0.63 in x 0.63 in should work.

Newtons to pounds force or vise-versa use 1 N = 0.2248 lbf