What Is the Drag Force on a Sky Diver at Different Speeds?

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Homework Help Overview

The discussion revolves around the drag force experienced by a sky diver at different speeds, specifically focusing on the calculations related to acceleration and drag force at speeds of 30.0 m/s and 53.0 m/s. The subject area includes concepts of dynamics and fluid resistance.

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to calculate the drag force at different speeds, questioning the validity of their approach for part (c) after finding results for parts (a) and (b). Some participants suggest using a proportional relationship between drag force and speed squared to derive a constant for further calculations.

Discussion Status

The discussion is ongoing, with some participants providing guidance on how to approach the calculation of drag force using proportional relationships. There is a lack of explicit consensus on the correctness of the original poster's calculations for part (c).

Contextual Notes

The original poster mentions that their answer for part (c) was marked incorrect by WebAssign, indicating potential issues with significant figures or calculation methods that are being explored in the discussion.

africanmasks
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Homework Statement



A sky diver of mass 79.5 kg jumps from a slow-moving aircraft and reaches a terminal speed of 53.0 m/s.

(a) What is the acceleration of the sky diver when her speed is 30.0 m/s?

What is the drag force on the diver when her speed is the following?
(b) 53.0 m/s (answer in N)
(c) 30.0 m/s (answer in N)

Homework Equations


The Attempt at a Solution



I found parts a and b (correct on Webassign), but I can't get part c.):

a.) a= 6.792 m/s2
b.) 779.1 N

Would part c.) just be: mg-ma?

(779.1)-(79.5)(6.792)
= 239.096 (WebAssign says it's incorrect)
 
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Drag force in air ia approximately proportional to v^2. So f = D*v^2.
Using the result from b, find D.
Use this value to solve c.
 
Thanks. I got it.
 
Your answer looks good. Does WebAssign concern itself with doing significant figures properly?
 

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