28. A wooden raft is made from logs having density 400. kg/m'. What fraction of the raft will be submerged in fresh water? Density = 1000. kg/m' 29. If the raft of #28 measures 2.00 m by 2.00 m by 0.250 m, how much weight can be put onto the raft before it completely submerges? 30. A canoe is 5.00 m long, weighs 600.0 N and is shaped like a half cylinder of radius 0.450 m. How much weight can be put into the canoe before it sinks