1. The problem statement, all variables and given/known data You are passing a construction site on the way to physics class, and stop to watch for a while. The construction workers appear to be going on a coffee break, and have left a large concrete block resting at the top of a wooden ramp connecting one of the building's upper floors to the ground. As soon as their backs are turned, the block begins to slide and takes about 2 seconds to reach the ground. You wonder how long the ramp is. You estimate the ramp is at an angle of about 37* to the horizontal, and your physics book gives the coefficient of kinetic friction (uk) between concrete and wood as 0.25 2. Relevant equations a= F/m vf=vi+at vf^2=vi^2+2ax 3. The attempt at a solution I found that: Fnety = Fn - Fgy = Fn - mgsin(37) = 0 Fn = mgsin(37) Fnetx = Ff - Fgx = uk(mg)sin(37) - mgcos(37) = ma a = uk(g)sin(37) - gcos(37) a = .25(-9.8)sin(37) + 9.8cos(37) a = 6.35 m/s^2 vf-vi = at vf = 6.35(2) vf = 12.7 m/s vf^2 - vi^2 = 2ax 12.7^2 = 2(6.35)x x = 12.7m I don't understand how this is wrong?