A sled is at the top of a snowhill that has a vertical height of 150 ft and slopes down with an angle of 20 degrees. If the coefficient of friction of the sled runners is .1 lb/lb, how fast is the sled going when it reaches the bottom of the hill, carrying a 165 lb person (weight includes sled), if it started from rest? Determine the total time for the sled to reach the bottom? how long would it take to reach the bottom if the slider gave it a 30 ft/sec sendoff?