1. The problem statement, all variables and given/known data The cable of an elevator of mass M = 3990 kg snaps when the elevator is a rest at one of the floors of a skyscraper. At this point the elevator is a distance d = 48.2 m above a cushioning spring whose spring constant is k = 21300 N/m. A safety device clamps the elevator against the guide rails so that a constant frictional force of f = 13784 N opposes the motion of the elevator. Find the maximum distance,x, by which the cushioning spring will be compressed. 2. Relevant equations Uspring= (kx^2)/2 Ugrav=mgh W=F*d=-U Ffriction=mu*N 3. The attempt at a solution Einitial=Efinal + deltaE Einitial=mgh Efinal=U + ((Ffriction*d) + (Ffriction*x)) mgh=(kx^2/2) + Ff*d + Ff*x After plugging in numbers, I then set the equation equal to zero, then factored - I got an answer of 16.6 m for the value of x - the answer was incorrect - I went with the idea that it was a conservation of energy problem, I also added the work done by the frictional force -I'm not sure what I am doing wrong, or of any alternative method - please help!!