Acceleration of a skydiver free falling(no parachute yet)9.8m/s^2 ?

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Discussion Overview

The discussion revolves around the acceleration of a skydiver in free fall, specifically addressing the effects of drag and weight as the skydiver approaches terminal velocity. Participants explore concepts related to acceleration, forces acting on the skydiver, and variations in terminal velocity based on body position during the fall.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions whether the acceleration of a skydiver in free fall is 9.8 m/s², suggesting that drag affects acceleration until terminal velocity is reached.
  • Another participant states that a skydiver's acceleration is slightly less than gravitational acceleration (g) due to drag until terminal velocity is achieved, at which point acceleration becomes zero.
  • A different viewpoint discusses how diving position affects terminal velocity, noting that a head-first dive results in a higher terminal velocity compared to a spread-eagle position, which increases drag.
  • Historical context is provided regarding a record-setting free fall by Joseph Kittinger, highlighting the extreme speeds and conditions experienced during high-altitude jumps.
  • One participant clarifies that at terminal velocity, the forces of weight and drag are equal, implying that weight equals drag at that point.

Areas of Agreement / Disagreement

Participants express varying views on the acceleration of a skydiver and the relationship between weight and drag at terminal velocity. There is no consensus on the initial acceleration value, and the discussion includes multiple competing perspectives on the effects of body position and drag.

Contextual Notes

Some assumptions regarding the conditions of free fall and the definitions of terminal velocity may not be fully articulated, and the discussion does not resolve the mathematical implications of the forces involved.

marshall4
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is the acceleration of a skydiver free falling(no parachute yet)9.8m/s^2 ?

When the skydiver reaches a new lower terminal velocity, what happens to his weight and drag?
 
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A skydivers acceleration is a bit less then g, due to drag, until he reaches terminal velocity. At terminal velocity his acceleration is 0.

When the skydiver reaches a new lower terminal velocity, what happens to his weight and drag?
I am not sure what this means.
 
If you dive head first, like you would into the water, you will reach a much higher terminal velocity than if you spread eagle. So, if you dive head first, reach the terminal velocity, and then go spread eagle, you will swoop through the air at an angle, and the "wind" will slow you to the new slower terminal velocity. Basically, there are two forces, weight and drag. Weight is a consant; drag is much higher spread eagle than head first.
 
If you go high enough in the atmosphere you can achieve very high speeds:

On August 27, 1960, the record was broken when a U.S. Air Force captain, Joseph Kittinger, Jr., set a world record for the highest balloon ascent, reaching an altitude of 102,800 feet (31,333 meters) in the Excelsior III. At the end of his ascent, he jumped out of his gondola and parachuted to the ground. That descent set another record for the longest parachute freefall—four minutes and 36 seconds—before his main parachute opened at 18,000 feet (5,486 meters). During his descent, he reached speeds of up to 614 miles per hour (1,149 kilometers per hour), approaching the speed of sound without an aircraft or space vehicle. He fell through air temperatures as low as minus 94 degrees Fahrenheit (minus 70 degrees Celsius). His flight and parachute jump demonstrated that it was possible to put a person into space and that fliers could exit their aircraft at extremely high altitudes and freefall back into the Earth's atmosphere.

http://www.centennialofflight.gov/essay/Lighter_than_air/20th_cent_records-2/LTA12.htm
 
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Originally posted by marshall4
When the skydiver reaches a new lower terminal velocity, what happens to his weight and drag?
At terminal velocity, weight = drag.
 

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