A model boat 1/100 size of its prototype has 0.12N of resistance when stimulating a speed of 5m/s of the prototype , what is the corresponding resistance in the prototype ? water is the fluid in both cases and frictional forces can be neglected.
Why the author need to transform the force into ρ(L^2)(v^2) ?
I know the unit of force is kg(m)(s^-2) , so , IMO , F is directly proportional to L only , right . but , not (L^3)
Fr = Fp / Fm