A 1.5 kilogram block is at rest on a ramp of height h. When the block is released, it slides without friction to the bottom of the ramp, and then continues across a surface that is frictionless except for a rough patch of width 10 cm that has a coefficient of friction µk=0.640 with the block. Find h if the block's speed after crossing the rough patch is 3.5 m/s.