Question

2. 11 Rowing. A boat carries N similar people, each of wbom can put power P into propelling the boat. Assuming that they each require the same volumeV of boat to accommodate them, show that the wetted area of the boat is A x (NV (here, as so often, the cox is ignored). Assuming inviscid flow, why might the drag force be proportional to pUA, where U is the speed of the boat and p the density of water? (In saying this, we are ignoring any drag due to waves created by the boat.) Deduce that the rate of energy dissipated by a boat travelling at speed U is proportional to pU3 A and put the pieces together to show that If we suppose, very crudely, that P and V are both proportional to body mass, is size an advantage to a rower? This example is based on a paper by McMahon [39], described in his book [40]; the theory agrees well with observed race times.

Answer 1

Solulfon → 2. es force 2 Perce x veleity) 3