For problem 26, I am all confused as to how to set up this problem. Could you give me some tips on how to start the problem?
The ratio of the ranges of two firings of the projectile is equal to the ratio of the initial (entirely x-directed) velocities because the time that it takes the ball to fall to the level of the floor is independent of the initial x-velocity. The initial velocity (i.e. just after firing) is determined by the potential energy stored in the spring before firing.