maths based riddles... See if you can answer them.
Discussion
kVA said:
Mate, the speed of the wind relative to Captain Birdseye stood on the boat is completely and utterly irrelevant in this riddle!!! Neither boat will win the race by having the sailor's hair more dishevelled than the other!!!
What matters is the speed relative to land, as that is how the race winner is being determined!
Incidentally, I note that the original objectors to my theory have gone awful quiet? have you just realised I'm right at last?
You have it totally backwards. The wind relative to the boat is the entirety of this problem.What matters is the speed relative to land, as that is how the race winner is being determined!
Incidentally, I note that the original objectors to my theory have gone awful quiet? have you just realised I'm right at last?
The water movement for both boats is similar, and therefore the water movement against the land is similar and can therefore be disregarded.
The answer is entirely determined by which boat can move with respect to the water. Boat B, has no apparent wind and therefore can move only with the current. Boat A does have apparent wind and can therefore move in relation to the water. It moves ahead of Boat B.
Add the land back in and hey presto, Boat A crosses the finish line first.
I give up...
I know I am right and am willing to prove it, if someone has the facility to generate a consistent 10 knot current for me to sail a boat on in still air!
Until then, I will just stick to the physics thanks:
I do understand about gravitational inertia, by the way... The reason it doesn't affect anything travelling at a constant speed is because the water is not actually flat - it follows the curve of the earth and is therefore perpendicular to the gravitational force. However, as soon as the speed changes for any reason, gravitational inertia will change the relative acceleration of the boat. It is a trivial thing in this example and something of a red herring, but it does exist and is an extra force that will influence the outcome of this race - albeit by a fraction of a second at the finish line!
The point that you can't seem to get into your head is that boat A will be slowed by air-resistance, so will not enjoy a constant 10 knot wind
Boat B has a constant 10 knot wind in the same direction as the current and therefore there will be no air-resistance and so it will go faster.
I know I am right and am willing to prove it, if someone has the facility to generate a consistent 10 knot current for me to sail a boat on in still air!
Until then, I will just stick to the physics thanks:
I do understand about gravitational inertia, by the way... The reason it doesn't affect anything travelling at a constant speed is because the water is not actually flat - it follows the curve of the earth and is therefore perpendicular to the gravitational force. However, as soon as the speed changes for any reason, gravitational inertia will change the relative acceleration of the boat. It is a trivial thing in this example and something of a red herring, but it does exist and is an extra force that will influence the outcome of this race - albeit by a fraction of a second at the finish line!
The point that you can't seem to get into your head is that boat A will be slowed by air-resistance, so will not enjoy a constant 10 knot wind
Boat B has a constant 10 knot wind in the same direction as the current and therefore there will be no air-resistance and so it will go faster.
marshalla said:
Will the pair of you please just f
k off to the Boats, planes and trains forum ? You have killed this thread.
The thread was dead before kVA resurrected it.k off to the Boats, planes and trains forum ? You have killed this thread. If others really want us to stop then I will but I think we are really getting somewhere now.
I can almost taste it in the air.
kVA said:
The point that you can't seem to get into your head is that boat A will be slowed by air-resistance, so will not enjoy a constant 10 knot wind
I completely and utterly agree, as I have said many times.It will be pushed backwards through the water so the wind speed will be 10 knots less however fast it is moving backwards.
Unfortunately you think that this is 10 knots backwards.
It isn't - it is far less.
Unless you think it is less?
In which case - how much less?
Can we agree in some extreme circumstances that the wind pushes the boat backwards (from boat B's position at say 4 knots???)
Would that be reasonable?
kVA said:
Incidentally, I note that the original objectors to my theory have gone awful quiet? have you just realised I'm right at last?
LOL.A boat with no current and a breeze against it:
If the boat does nothing - it will slowly drift backwards.
If the boat raises sails square on to the wind - it will drift backwards more quickly.
If the boat 'sails' into the wind - it will move forward.
I.e. a boat can move forwards faster than the current (in this case zero).
kVA said:
Mate, the speed of the wind relative to Captain Birdseye stood on the boat is completely and utterly irrelevant in this riddle!!! Neither boat will win the race by having the sailor's hair more dishevelled than the other!!!
What matters is the speed relative to land, as that is how the race winner is being determined!
Incidentally, I note that the original objectors to my theory have gone awful quiet? have you just realised I'm right at last?
I just want to quote this for posterity.What matters is the speed relative to land, as that is how the race winner is being determined!
Incidentally, I note that the original objectors to my theory have gone awful quiet? have you just realised I'm right at last?
kVA - from your last couple of posts it seems that you might finally agree that there is NO difference between
1. Boat on still water with a 10 knot breeze.
2. Boat in a 10 knot current with still air.
(You have agreed to disregard whatever your "gravitational inertia" is as tiny - right?)
So - 1 & 2 are the same right?
kVA said:
walm said:
Absolutely not - RELATIVE TO THE BOAT.
From the frame of reference of the water what happens is:
Boat moving downwind slightly from the wind pushing against the hull and spars.
Sails go up and the boat moves even faster downwind as there is more for the wind to push.
Of course stationary on the water the wind will always be 10knots!!
While you are on the boat the wind you feel is obviously 10 knots LESS the speed you are going downwind.
THIS IS EXACTLY WHAT HAPPENS ON THE OTHER BOAT.
Mate, the speed of the wind relative to Captain Birdseye stood on the boat is completely and utterly irrelevant in this riddle!!! Neither boat will win the race by having the sailor's hair more dishevelled than the other!!!From the frame of reference of the water what happens is:
Boat moving downwind slightly from the wind pushing against the hull and spars.
Sails go up and the boat moves even faster downwind as there is more for the wind to push.
Of course stationary on the water the wind will always be 10knots!!
While you are on the boat the wind you feel is obviously 10 knots LESS the speed you are going downwind.
THIS IS EXACTLY WHAT HAPPENS ON THE OTHER BOAT.
What matters is the speed relative to land, as that is how the race winner is being determined!
Incidentally, I note that the original objectors to my theory have gone awful quiet? have you just realised I'm right at last?
In fact it's a bit cheeky of you to suggest that after your recent silence while you travelled abroad
Edited by Alfanatic on Friday 23 September 16:32
Alfanatic said:
kVA said:
Mate, the speed of the wind relative to Captain Birdseye stood on the boat is completely and utterly irrelevant in this riddle!!! Neither boat will win the race by having the sailor's hair more dishevelled than the other!!!
What matters is the speed relative to land, as that is how the race winner is being determined!
Incidentally, I note that the original objectors to my theory have gone awful quiet? have you just realised I'm right at last?
No, you're still wrong, in fact the list of things that you've been wrong about is building.What matters is the speed relative to land, as that is how the race winner is being determined!
Incidentally, I note that the original objectors to my theory have gone awful quiet? have you just realised I'm right at last?
So now you think that a boat going faster against the wind will win a race, over a measured distance on land, against a boat that goes faster relative to the land?
Jeez...
Please, please, please - somebody set up an experiment!!! Boat A will never ever, in a million years, move at 10 knots: To do so, it would have to weigh nothing, have 100% hydrodynamic co-efficient of drag and 0% aerodynamic co-efficient of drag... So there never will be a 10 knot 'apparent wind' and the more sails you put up the slower it will go and the more hydrodynamic you make the hull, the more water will slip past the hull and the less 'apparent wind' it will create.
This is not a sailing riddle - it is a very simple matter of physics - there is no such thing as a free lunch and you can't create energy from nothing.
If the consensus is that we should end this debate I am happy to stop posting about yachts... However, I will never admit defeat on this until someone categorically proves me wrong with an actual experiment - As I said before, I KNOW I am right, everyone else just THINKS they are...
walm said:
I just want to quote this for posterity.
kVA - from your last couple of posts it seems that you might finally agree that there is NO difference between
1. Boat on still water with a 10 knot breeze.
2. Boat in a 10 knot current with still air.
(You have agreed to disregard whatever your "gravitational inertia" is as tiny - right?)
So - 1 & 2 are the same right?
No they are not - please read my reply before you selectively mis-quote my answer to your original questionkVA - from your last couple of posts it seems that you might finally agree that there is NO difference between
1. Boat on still water with a 10 knot breeze.
2. Boat in a 10 knot current with still air.
(You have agreed to disregard whatever your "gravitational inertia" is as tiny - right?)
So - 1 & 2 are the same right?
kVA said:
No they are not - please read my reply before you selectively mis-quote my answer to your original question
Sorry - I was cross-quoting!So you said:
kVA said:
1.) No matter how many sails the sailor raises in a 10 knot wind, the wind will still be blowing at 10 knots
2.) As soon as the sailor raises a sail, the boat will no longer be travelling at the same speed as the current, as air-resistance will slow it down: The more sails he or she raises, the slower it will go - and so there no longer is a 10 knot wind
I have cut out all the blather about "gravitational inertia" as you admit it is tiny (whatever it is).2.) As soon as the sailor raises a sail, the boat will no longer be travelling at the same speed as the current, as air-resistance will slow it down: The more sails he or she raises, the slower it will go - and so there no longer is a 10 knot wind
So you have explained 1 & 2 and I replied that the same happens for both.
The wind on the boat is less than 10 knots because the boats both move a little downwind.
Do you agree with this?
In other words - will Captain Birdseye feel the same strength wind through his beard on both 1 & 2?
I thought you agreed that yes he would??
I just want to check.
tank slapper said:
There we have your complete lack of understanding demonstrated in one sentence. Go and learn about frames of reference.
Wow... there are some patronising people gathering on this thread...Go and read my answer to the original question - in it's entirety...
If you believe the two are the same, it is you who needs to go and learn about hydrodynamics and aerodynamics
kVA said:
hydrodynamics and aerodynamics
You keep mentioning these.Please give an example for Capt 1 and Capt 2 that will show how they experience different hydrodynamic or aerodynamic forces.
Just pick one.
For example - the guy on still water will feel a stronger breeze.
Is this what you believe?
Please give AN EXAMPLE.
Just ONE force left or right, up or down whatever.
That will be DIFFERENT on the two boats.
kVA said:
Alfanatic said:
kVA said:
Mate, the speed of the wind relative to Captain Birdseye stood on the boat is completely and utterly irrelevant in this riddle!!! Neither boat will win the race by having the sailor's hair more dishevelled than the other!!!
What matters is the speed relative to land, as that is how the race winner is being determined!
Incidentally, I note that the original objectors to my theory have gone awful quiet? have you just realised I'm right at last?
No, you're still wrong, in fact the list of things that you've been wrong about is building.What matters is the speed relative to land, as that is how the race winner is being determined!
Incidentally, I note that the original objectors to my theory have gone awful quiet? have you just realised I'm right at last?
So now you think that a boat going faster against the wind will win a race, over a measured distance on land, against a boat that goes faster relative to the land?
Jeez...
Please, please, please - somebody set up an experiment!!! Boat A will never ever, in a million years, move at 10 knots: To do so, it would have to weigh nothing, have 100% hydrodynamic co-efficient of drag and 0% aerodynamic co-efficient of drag... So there never will be a 10 knot 'apparent wind' and the more sails you put up the slower it will go and the more hydrodynamic you make the hull, the more water will slip past the hull and the less 'apparent wind' it will create.
This is not a sailing riddle - it is a very simple matter of physics - there is no such thing as a free lunch and you can't create energy from nothing.
If the consensus is that we should end this debate I am happy to stop posting about yachts... However, I will never admit defeat on this until someone categorically proves me wrong with an actual experiment - As I said before, I KNOW I am right, everyone else just THINKS they are...
Alfanatic said:
The only reason this debate is continuing is because you seem unable to let it go without having the last word. I was happy to make no further contribution until you tried to put words into my mouth.
No he does want to give up.I am most likely the one dragging it on.
Sorry.
I just thought I was making some headway (<------ see what I did there?).
If we can persuade kVA that frames of reference are VERY relevant here then we might just get there.
But I am not sure we can so perhaps I should just let it go.
Dr Jekyll said:
You are proven wrong by experiment every single time a boat sails upwind relative to the water. Do you accept that a sailing boat on still water wih a wind fom the north can head north?
Yes I do and go back a few pages to see why this is completely and utterly irrelevant in this puzzle.I have sailed upwind in still water many, many times, but I've never been able to beat the tide when there is no wind... it just can't be done.
For the sake of the RNLI, please don't try and prove me wrong in a narrow channel - you will need rescuing at some point, unless you are very lucky or have a powerful engine as a back-up.
walm said:
No he does want to give up.
I am most likely the one dragging it on.
Sorry.
I just thought I was making some headway (<------ see what I did there?).
If we can persuade kVA that frames of reference are VERY relevant here then we might just get there.
But I am not sure we can so perhaps I should just let it go.
You are right...I am most likely the one dragging it on.
Sorry.
I just thought I was making some headway (<------ see what I did there?).
If we can persuade kVA that frames of reference are VERY relevant here then we might just get there.
But I am not sure we can so perhaps I should just let it go.
...I do want to end this debate.
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