1. The problem statement, all variables and given/known data A 1209 kg safe is 1.54 m above a heavy-duty spring when the rope holding the safe breaks. Thr safe hits the spring and compress it 53 cm. What is he spring constant of the spring? 2. Relevant equations K=mV^2/2 U=mgh Ki+Ui=Kf+Uf 3. The attempt at a solution I thought I understood momentuem and energy but not anymore. Here is what I did.... Ui=mgh= 2*9.8*1.54 Kf=mV^2/2 Then solved for V and got 5.494 m/s Then used that velocity for the spring constant by using...... U=k(delta x)^2/2 K=mV^2/2 then solved for k and got 129912 N/m...... but that is coming up wrong what am i doing wrong.