A child on a sled slides (starting from rest) down an icy slope that makes an angle of 15◦ with the horizontal. After sliding 20 m down the slope, the child enters a flat, slushy region, where she slides for 2.0 s with a constant negative acceleration of −1.5 m/s² with respect to her direction of motion. She then slides up another icy slope that makes a 20◦ angle with the horizontal.
How fast was the child going when she reached the bottom of the first slope? How long did it take her to get there?