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Old 03-23-15 | 11:02 AM
  #48  
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Brian Ratliff
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Joined: May 2002
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From: Near Portland, OR

Bikes: Three road bikes. Two track bikes.

Originally Posted by greenlight149
Two balls are dropped from the top of a building, one is heavier the other one is lighter, they hit the ground at exactly the same time. If you change the shape of one ball so it has more frontal area, thus more drag, it will take longer to reach the bottom. Therefore, gravitational acceleration is independent of mass. If a heavier rider and a light rider can have the same coefficient of drag, they will descent at the same speed.
incorrect. Do the math. We'll wait.

Without drag, the light and heavy objects will accelerate due to gravity at the same rate because gravitational force is acting unopposed. With drag, the heavier object accelerates faster than the lighter one even assuming equivalent coefficients of drag. Gravitational force acts on the higher mass of heavy objects more than light objects while drag is proportional (squared, in the case of aero drag) to velocity and is not dependent on mass. Thus, the same drag force acting on a heavy vs. light object creates a resultant force that is larger for the heavier object and smaller for the lighter object, causing the heavier object to accelerate faster.
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