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Q5. A ship has a length of 130 m and floats in the sea water of density 1025 kg/m³.  A model of this ship has a length of 5 m and a wetted surface area of 6 m2.  The model has a total resistance of 45 N when towed at 1.85 m/s in fresh water of density 1000 kg/ m³.

(a) Using the data below, calculate EACH of the following:

(i) the ratio of residuary resistance to total resistance for the model; (5)

(ii) the ratio of residuary resistance to total resistance for the ship at the corresponding speed. (8)

(b) State why the two ratios should be different. (3)

The frictional coefficient for the model in fresh water is 1. 694

The frictional coefficient for the ship in sea water is 1. 418

Speed in m/s with the speed index (n) for ship and model 1.825