Can these please be solved on paper with a step by step explanation and a body diagram when necessary Answers:7) 31N8) -0.25,09) x=20cm y=20cm z=16cm

7) The potential energy function of a certain force acting on an "object is U(x) = 3x - 5x + 9. Calculate the force on the object when the object is at x = 2 m. 8) A uniform sheet of wood 6 m on a side has a square piece 2 m on a side cut out of it. The cut-out is centered vertically on the right side of the sheet. The center of the sheet is located at the origin. See diagram. Find the center of mass of the sheet. 9) A cubical box has been constructed from metal plates 2 of uniform density and negligible thickness. The box is open at the top. See diagram. The sides of the cube are 40 cm. Find the x, y, and z coordinates of the center of mass of the box