A raft is made of 16 logs lashed together (4 by 4) on salt water (1027 kg/m^3). Each is 40 cm in diameter and has a length of 6 m. How many people can the raft hold before they start getting their feet wet, assuming the average person has a mass of 75 kg? Do not neglect the weight of the logs. Assume the density of wood is 600 kg/m^3. b.) A 68 kg person decides to make a raft out of empty 1.0-L soda bottles and duct tape. Neglecting the mass of the duct tape and plastic in the bottles, what minimum number of soda bottles will the person need to be able stay dry on the raft? c.) How would part b change if each bottle is 25 grams in mass?