Winston is holding the ladder for his friend Jil. The 20-foot ladder is resting against the side of the building. Winston walks away to check something on his phone and the ladder begins to slide down. Suppose that the ladder is sliding down the wall at a rate of 10ft/sec. How fast of the base of the ladder moving when it hits Winston? (Note that the top of the ladder is 4 feet from the ground at this time). Include units in your answer and round to one decimal place.