N identical carts are connected to each other using strings of negligible mass. A pulling force F is applied on the first cart and the system moves without friction along the horizontal ground. The tension in the string connecting `4^(th) "and" 5^(th)` cart is twice the tension in the string connecting `8^(th) "and" 9^(th)` cart. Find the total number of carts (N) and tension in the last string.

Answer

N = 12 ; Tension = `(F)/(N) = (F)/(12)`