OK this sounds like a stupid question but someone at the pool told me that my hand needs to be open with my fingers apart when I swim. i normally cup it which is what I thought was the best way. Today I tried my fingers together and my thumb out a little bit from the hand.
The cupped hand seemed best but what do the experts say?
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I don't doubt that F=ma plays a role in swimming, after all my original question was what the relative contributions of force from accelerating water are versus force from viscosity/drag.
The problem with the passage I quoted was that it got the terms all wrong and the relative contributions all wrong. The passage defined m to be the mass of the swimmer and a to be the acceleration of the swimmer. I think we would all be happy if we could maintain the speed we had coming off the wall right? To maintain velocity is to have zero acceleration and therefore F=ma tells us zero force is required! In reality to maintain speed the propulsive force exerted by the swimmer must be equal and opposite to the drag forces thereby summing to zero. In the original passage the author said:
"Although it is not totally accurate because of the friction of the water it does explain the basic force a swimmer must exert."
This is completely untrue for a swimmer moving at constant velocity (acceleration is zero), the "friction" (really drag) is the basic force not the inaccuracy!
Lindsay, are you confusing Velocity with Force ? F=MA is Zero and still move forwards can only be true in a Vacuum, and that after an initial propulsion. The actual velocity of the swimmer could be expressed as the sum of: F=MA ( of swimmer ) minus F ( where F is force of total Drag )
The water pushes back almost as strongly as we push against it. If there is no force exerted by the swimmer we STOP. The force exerted must be greater than the total drag to Accelerate or Equal to total drag to move at a constant velocity.
The original question bout hand position is also well addressed in Colwins book. In short the larger the surface area the better, and fingers should be forward of the palm to hold pressure against the water rather than be bent backwards, which allows pressure to slip.
:)
I don't doubt that F=ma plays a role in swimming, after all my original question was what the relative contributions of force from accelerating water are versus force from viscosity/drag.
The problem with the passage I quoted was that it got the terms all wrong and the relative contributions all wrong. The passage defined m to be the mass of the swimmer and a to be the acceleration of the swimmer. I think we would all be happy if we could maintain the speed we had coming off the wall right? To maintain velocity is to have zero acceleration and therefore F=ma tells us zero force is required! In reality to maintain speed the propulsive force exerted by the swimmer must be equal and opposite to the drag forces thereby summing to zero. In the original passage the author said:
"Although it is not totally accurate because of the friction of the water it does explain the basic force a swimmer must exert."
This is completely untrue for a swimmer moving at constant velocity (acceleration is zero), the "friction" (really drag) is the basic force not the inaccuracy!
Lindsay, are you confusing Velocity with Force ? F=MA is Zero and still move forwards can only be true in a Vacuum, and that after an initial propulsion. The actual velocity of the swimmer could be expressed as the sum of: F=MA ( of swimmer ) minus F ( where F is force of total Drag )
The water pushes back almost as strongly as we push against it. If there is no force exerted by the swimmer we STOP. The force exerted must be greater than the total drag to Accelerate or Equal to total drag to move at a constant velocity.
The original question bout hand position is also well addressed in Colwins book. In short the larger the surface area the better, and fingers should be forward of the palm to hold pressure against the water rather than be bent backwards, which allows pressure to slip.
:)
