26 Jun '16 12:11>3 edits
Here is a physical puzzle I thought up but I don't know what's the answer to it;
As surely most people would know, the way a conventional sailing ship is able to sail again the wind when the wind is, say, blowing exactly southwards when the ship is required to move exactly northwards, is in a zigzag pattern because it cannot sustainable move directly exactly northwards but at an angle to northwards hence the need to zigzag.
But what if, instead of having a sail on the wind powered ship, we place a wind turbine on it to convert some of the wind energy into electric energy.
And we also put a water propeller (just like on most conventional modern ships) at the back of the ship to push it forward but this water propeller is entirely powered by an electric motor that in turn gets all of its electricity from the wind turbine. Lets say both the electric motor for the water propeller and the electric generator of the wind turbine is 99.9% energy efficient so there is negligible lose of energy there.
So would such a wind turbine ship be able to sustainable move directly exactly northwards against an exactly southward blowing wind without zigzagging?
Or, if you tried that without zigzagging, would the backward force of the wind turbine blades exerted by the wind against it be greater than the forward force exerted by the water propeller at the back of the ship thus you would still have to zigzag?
I don't know how to work this one out.
As surely most people would know, the way a conventional sailing ship is able to sail again the wind when the wind is, say, blowing exactly southwards when the ship is required to move exactly northwards, is in a zigzag pattern because it cannot sustainable move directly exactly northwards but at an angle to northwards hence the need to zigzag.
But what if, instead of having a sail on the wind powered ship, we place a wind turbine on it to convert some of the wind energy into electric energy.
And we also put a water propeller (just like on most conventional modern ships) at the back of the ship to push it forward but this water propeller is entirely powered by an electric motor that in turn gets all of its electricity from the wind turbine. Lets say both the electric motor for the water propeller and the electric generator of the wind turbine is 99.9% energy efficient so there is negligible lose of energy there.
So would such a wind turbine ship be able to sustainable move directly exactly northwards against an exactly southward blowing wind without zigzagging?
Or, if you tried that without zigzagging, would the backward force of the wind turbine blades exerted by the wind against it be greater than the forward force exerted by the water propeller at the back of the ship thus you would still have to zigzag?
I don't know how to work this one out.