please help!!! this is all about buoyant force, Physics.
2006-09-15 23:36:00 · 14 answers · asked by jaw_fil 1 in Science & Mathematics ➔ Physics
Everyone else talked about the higher bouyancy due to the higher density of salt water. But the reason that makes it easier to swim is that you need to expend less energy just to keep your head above water and can expend more energy to propel your body in the desired direction.
You swim by applying force to water molecules to accelerate them away from you. This force applied to you is what accelerates you. You can more effectively apply that force if the fluid molecules are heavier. That could let you swim a little faster. Of course, the molecules you collide with are also heavier, so that would slow you down a little. These effects are minor compared to the benefit of bouyancy.
2006-09-16 05:50:48 · answer #1 · answered by Frank N 7 · 0⤊ 0⤋
You mean b/c of salt making you float?
Let's take a moment and look at an object in water and Archimedes Principle. If you place a 1 cubic foot object that weighs 63 lbs into fresh water, the object is displacing 62.4 lbs of water, but weighs 63 lbs. This object will be negatively buoyant - it will sink. It is however being buoyed up with a force of 62.4 lbs, so if we weighed it in the water it would only weigh .6 lbs.
If we put the same object into salt water, it would still weigh 63 lbs, but would be buoyed up by a force of 64 lbs, and it would float. It would be positively buoyant in salt water. To make the object neutrally buoyant in salt water, we would have to add 1 lb of weight to the object without changing its size (without changing is displacement). Then it would weigh 64 lbs, and be buoyed up with a force of 64 lbs, thus being neutrally buoyant.
2006-09-15 23:37:06 · answer #2 · answered by Anonymous · 3⤊ 0⤋
Salt in the water helps you float. In fact, the Dead Sea is so full of it most people don't need lifesavers to stay buoyant.
2006-09-15 23:38:54 · answer #3 · answered by Studier Alpha 3 · 0⤊ 0⤋
It is all because of the salt - the more saltier the water is, the more easier swimming is (because the buoyant force is greater).
2006-09-15 23:44:03 · answer #4 · answered by Elize 3 · 0⤊ 0⤋
More density. What this means is our bodies are more buoyant in sea than swimming pool
2006-09-15 23:41:40 · answer #5 · answered by toietmoi 6 · 0⤊ 0⤋
Density of sea water is 1025 kg/m^3 whereas the density of water is 998 kg/m^3.
In order to float a man weighing 50 kg needs to expel only 0.488m^3 of sea water whereas he needs to expel 0.506 m^3of water.
That is in ordinary water he has to expel 18000 cc of water than sea water.
Thus in ordinary water he sinks more than in sea water to have the same buoyant force upward.
Thus he feels easy to swim in sea water than in ordinary water.
2006-09-16 00:23:06 · answer #6 · answered by Pearlsawme 7 · 0⤊ 0⤋
the salt helps you to float in the water. so probably easier to swim in seawater. However iff the sea water is cold it is sometimes quite hard for the person swimming to breath
xx
2006-09-15 23:47:12 · answer #7 · answered by Anonymous · 0⤊ 0⤋
because in the sea more or less than 70% normally contain salt. that's why the bigger percentage of the salt contain the hardest you sinking under water. for example the dead sea. there's no life in there and you can swim easily without sinking. thank.
2006-09-15 23:54:01 · answer #8 · answered by Anonymous · 0⤊ 0⤋
It is something to do with the salt in sea water increasing the density of water, so human body displaces it less.
2006-09-15 23:38:32 · answer #9 · answered by Bebe 4 · 0⤊ 0⤋
Salt water creates greater buoyancy!
2006-09-15 23:38:00 · answer #10 · answered by Bear Naked 6 · 0⤊ 0⤋