When a ship is moving through the water, the resistance to its motion partly comes from making waves. This is called the "Wave Making Resistance". The other part of the resistance is known as "Frictional Resistance". For one ship, Frictional Resistance is 80 % of the total resistance. The remainder comes from making waves. The frictional resistance is F when the ship is at terminal velocity. Write an equation for Fb, the driving force propelling the ship, in terms of Fr. For example, if you think that the driving force is twice as strong as the frictional resistance, you would write FD = 2Ff.