Problem # 5 A spring has a natural length of 18 inches. The spring has the following property: Q force of 20 lh is applied, the spring's length becomes 24 inches. What is the work required to stretch the spring from a length of 21 inches to a length of 26 inches? Problem # 6 1 A cable that weighs E kgj'rneter is lifting a load of 150 kg (mass = 150 kg) that is initially at the bottom of a 50 meter shaft. How much work is required to lift the load hill-| of the way up the shaft? (weight 2 mass * 9.8) Problem # 7 Determine the length of x = 4(3 + 31?, 1 E y S 4. Problem # 8 Find the center of mass for the region bounded by y = 4- x2 that is in the rst quadrant. Rotate the region bounded by x = y2 6y -I- 10 and x = 5 about the yaxisl