7: A mass is at rest on a spring in a liquid with p = 1500 kg/ n13 (above left). The spring has a force constant of 200 N / H1 and it has been compressed a distance of 0.1 Hi. If M' = 5 kg, determine the density of the mass. 8: A box with volume V and density p is supported as shown (previous page middle). The lower end of the box is in water (with density pwater = 1000 kg/m3) and the upper end is in oil (with density poi] = 800 kg/m3). Assume that a volume (0751/) is in the water. Determine the box density ,0 IF the tension in the cable is zero. 9: A 75 kg convict oats on a raft (ll/frag : 60 kg1 praft : 300 kg/mg) in an attempt to escape prison (previous page right). The convict is completely above the water surface but part of the raft is underwater. Determine the fraction of the raft's volume which is below the surface of the water. Use pwater = 1000 kg/m3