Question

Robin is making a mobile to hang over her baby sister's crib. She purchased four stuffed animals: a teddy bear (16 g), a lamb (18 g), a little pony (22 g) and a bird (15 g). She also purchased three small wooden dowels, each 14 cm long and of mass 7 g, and thread of negligible mass. She wants to hang the bear and the pony from the ends of the first dowel and the lamb and the bird from the ends of the second dowel. Then, she wants to suspend the two dowels from the ends of the middle dowel and hang the whole assembly from the ceiling. Find where the middle thread should be attached to the middle dowel and where the ends of the middle dowel should be attached to the first and second dowel so that the entire assembly will hang level.