A ship, on which airplanes land, has an airstrip of 70 m. The ship uses three different techniques to stop airplanes when they are landing. The first technique is to use a cable reel of radius 0.4 m, around which a non-elastic rope is coiled. The reel is to be rotated about its axle - which is a fixed point (doesn't move) - opposite to a friction force cause by two brake pads in contact with the outer radius of the reel that is 0.6 m. The coefficient of static and kinetic friction between a brake pad and the reel are 0.45 and 0.41, respectively. The second technique is to use an elastic rope that restrains the airplane in a way that it exerts a force, on the airplane, proportional to the rope extension. The third technique is to use a piston - located inside a cylindrical water tank which is lying horizontally - such that when an airplane lands, the piston pumps water out, through a perforation at the end of the tank, by means of a non-elastic rope between the airplane and the piston. In such a case, the pressure acting against the piston is proportional to V^2 (velocity squared) of the piston. If the airplane has a mass of 3000 kg, and a velocity of 48.9 m/s as it touches the ship. And if the airplane braking system is not used, but rather, a technique (of the three) starts to decelerate the airplane as soon as it touches the ship. (1) F=a(b)^c Use this form to write expressions for the force supplied by the three techniques. Knowing that F is the force, a and c are constants, and b is replaced by: velocity or acceleration or time or displacement. (2) For the first and second techniques, find the maximum acceleration experienced by the airplane and determine at what stage this acceleration is experienced. (3) If the braking system of the airplane is used, where it applies a total horizontal force of 6000 N to slow the airplane down, as soon as it touches the ship. Find the maximum acceleration experienced by the airplane when it is landing, if the third technique is used. This question has 13 branches, I solved all, except for these 3.. For the first branch, I am not sure if the constants are to be replaced or not. And about the first technique, I think that the force is dependent on time in a way (the coefficient of static friction) For the second branch, I know that the maximum acceleration occurs ; for tech. 1 at the very begging , and for tech. 2 when velocity=0 , but I am unable to find it. For the third branch, I don't know how/where to start I will be thankful if you can explain.