A seagoing crane lifts a sealed safe from a sunken shipThe average density of the safe is 5.3 grams/cc and its mass is 120kgWhat is the tension in the lifting cable when the safe is still submerged?
What's the volume of the safe? Convert the safe density to kg/m^3: (5.3 g/cc) (1 kg/1000 g) (10^6 cc/m^3) 5300 kg/m^3 120 kg 1 m^3/5300 kg .0226 m^3 So the safe is displacing that much waterWhat's the weight of that much water? Density of water is 1000 kg/m^3.0226 m^3 1000 kg/m^3 22.6 kg So the safe appears to have a mass of 120 - 22.6 kgSo its apparent weight is W mg 97.4 kg 9.8 m/s^2 955 NAnd that's the tension in the cable.
