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Old 10-20-14, 08:23 AM
  #187  
cyccommute 
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Originally Posted by Andy_K
No!!!!

When accelerating a massive body from rest, the force needed for accelerating is proportional to the mass being moved. When applying force to a moving body to counteract a resisting force and maintain constant velocity the force required is exactly equal to the resisting force. Unless the resisting for is dependent on mass (which air resistance is not) then force needed to maintain constant speed is also independent of mass. Air resistance is determined (mostly) by frontal cross-sectional area, and so we big fellows on upright bikes do still bear a bigger burden than are slender brethren riding in a nice tucked position, but it's not because of weight.
You cannot have force independent of mass. Simply can't happen. The definition of force is mass times acceleration. Without both of those items, you don't have force. The larger frontal area has a role but you still have to provide force to keep the bike moving. More importantly, you have to provide force to move the air out of the way. A larger frontal area requires more force from the rider to move the system. Since the force needed to move the air is equal to the force needed to move the bike and the bike/rider system has mass, a larger mass requires more force to move it and more force to maintain constant speed.
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