I am having some problems, I am on the work energy theorem and I had to do some problems for homework. For one of the questions I was not given enough information. I am supposed to find the initial velocity, when they tell us the final velocity is zero, the coefficient of friction is 0.42 and the distance in the x direction is 88m. But I don't understand how I can find the initial velocity like that. I know: v^2=1/2mv^2 and it says mass doesn't matter. Thanks in advance.