Laws of Motion Part 1

A system to 10 balls each of mass 2‌kg are connected via massless and unstretchable string. The system is allowed to slip over the edge of a smooth table as shown in figure. Tension on the string between the 7‌th ‌ and 8‌th ‌ ball is ____N when 6‌th ‌ ball just leaves the table.