A transport plane takes off from a level landing field with two gliders in tow, one behind the other. The mass of each glider is 700 , and the total resistance (air drag plus friction with the runway) on each may be assumed constant and equal to 2400 . The tension in the towrope between the transport plane and the first glider is not to exceed 12000 .
Part A: If a speed of 40 is required for takeoff, what minimum length of runway is needed? Express your answer using two significant figures.
Part B: What is the tension in the towrope between the two gliders while they are accelerating for the takeoff? Express your answer using two significant figures.