A child slides down a snow-covered slope on a sled. At the top of the hill, her mother gives her a push to start her off with a speed of 1.40 m/s. The frictional force acting on the sled is one-fifth of the combined weight of the child and the sled. 1) If she travels for a distance of 25.0 m and her speed at the bottom is 4.00 m/s, calculate the angle that the hill makes with the horizontal. (Express your answer to two significant figures.)