Why am I getting a negative!? (Energy conservation) 1. The problem statement, all variables and given/known data 2kg block slides on a rough table with uk = 0.3, just before the block hits the spring V0 = 1.3 m/s. k = 120N/m. How far is the spring compressed? 2. Relevant equations Ki + Us = Kf + Us - Eth 3. The attempt at a solution Okay just before it touches the spring, what energy does it have? Ki = 1/2(2)(1.3)^2 = 1.68 J 1.68J + 0 = 0 + 1/2kx^2 -fx 0 = 1/2kx^2-mgukx-1.68 0 = 60x^2 -5.88x - 1.68 x= 0.22 or x= -0.13 Why is my answer negative!!??? The only thing i can think of that intially the spring is not compressed. (x=0) Once you compress the spring, the spring must get smaller, what's smaller than 0? -0.13 Can anyone clearly explain to me why this is negative!!?