Answer:
(a) Length =136.58 m
(b) T=5995 N
Step-by-step explanation:
for the glider in the back
T - 1900 = 700 a
for the glider in front
12000-T -1900 = 700a
add equations
12000-3800 = 1400 a
a=5.85 m/s^2
v^2 = v0^2 + 2 a x
40^2 = 2*5.85*x
Length =136.58 m
b) plug the a back into one of the previous formula
T - 1900 = 700*5.85
T=5995 N