Anybody good at physics??

Here's my pseudo-science contribution to the thread: * Drag forces are not directly related to mass but you still have to accelerate your mass to overcome the drag forces in order to maintain a constant velocity. F=ma does apply here. Being heavier hurts. * While drag forces are not directly related to mass, they are related to cross-section and surface area. If you increase your girth, you increase your drag. * Bouyancy makes a difference. Riding higher reduces the surface area and cross-section exposed to the water. Where you pack on that extra weight has a lot to do with whether or not this really helps. If only we could add fat in full body suit shapes. * Pushing off a wall or starting block requires more force for a heavier person. You are accelerating your mass so there is really no getting past f=ma. Work is force applied over a distance. No need to go into that. * I suspect there may be other forces at work other than drag. Wave generation is an interesting one and it turns out that being a little bigger might be an advantage. When you swim, you generate a wave. You actually make two waves, a bow wave and a stern wave. For non-planing boats, there's a point at which going faster becomes increasingly difficult due the interaction between these waves. Turns out the point at which things get harder is a function of the length of the waterline where a larger person would be better off. Don't know if this applies to humans swimming but I suspect it would. My conclusion: It is hard to tell if packing on a few extra pounds really makes that much difference in swimming. Modeling a rigid body moving through the surface of the water is complicated enough. Accurately modeling a human thrashing about on the surface of the water is not going to happen with our current technology. So, there is not way to do a real objective analysis. We are left with anecdotal evidence like, "I shaved 2 seconds off my 50 free after I lost 10 lbs." Or maybe, "some fat guy blew me away in the 50 free last week. I guess the extra weight doesn't hurt him at all." It definitely isn't the liability it would be in running or cycling.

Here's my pseudo-science contribution to the thread: * Drag forces are not directly related to mass but you still have to accelerate your mass to overcome the drag forces in order to maintain a constant velocity. F=ma does apply here. Being heavier hurts. * While drag forces are not directly related to mass, they are related to cross-section and surface area. If you increase your girth, you increase your drag. * Bouyancy makes a difference. Riding higher reduces the surface area and cross-section exposed to the water. Where you pack on that extra weight has a lot to do with whether or not this really helps. If only we could add fat in full body suit shapes. * Pushing off a wall or starting block requires more force for a heavier person. You are accelerating your mass so there is really no getting past f=ma. Work is force applied over a distance. No need to go into that. * I suspect there may be other forces at work other than drag. Wave generation is an interesting one and it turns out that being a little bigger might be an advantage. When you swim, you generate a wave. You actually make two waves, a bow wave and a stern wave. For non-planing boats, there's a point at which going faster becomes increasingly difficult due the interaction between these waves. Turns out the point at which things get harder is a function of the length of the waterline where a larger person would be better off. Don't know if this applies to humans swimming but I suspect it would. My conclusion: It is hard to tell if packing on a few extra pounds really makes that much difference in swimming. Modeling a rigid body moving through the surface of the water is complicated enough. Accurately modeling a human thrashing about on the surface of the water is not going to happen with our current technology. So, there is not way to do a real objective analysis. We are left with anecdotal evidence like, "I shaved 2 seconds off my 50 free after I lost 10 lbs." Or maybe, "some fat guy blew me away in the 50 free last week. I guess the extra weight doesn't hurt him at all." It definitely isn't the liability it would be in running or cycling.