Physics I question Skydiver falling

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SUMMARY

The terminal speed of a 79 kg skydiver modeled as a rectangular box with dimensions 25 cm x 39 cm x 1.8 m can be calculated using the drag equation. The correct formula for drag is F_d = \frac{1}{2} \rho A D v^2, where \rho is the air density, A is the cross-sectional area, and D is the drag coefficient. The user initially miscalculated the drag force and used an incorrect coefficient, leading to an erroneous terminal speed of 196.7 m/s. The correct approach requires accurate values for air density and the drag coefficient to determine the terminal velocity accurately.

PREREQUISITES
  • Understanding of drag force and terminal velocity concepts
  • Familiarity with the drag equation F_d = \frac{1}{2} \rho A D v^2
  • Knowledge of air density values under standard conditions
  • Ability to calculate cross-sectional area from object dimensions
NEXT STEPS
  • Research the standard value of air density at sea level (approximately 1.225 kg/m³)
  • Learn how to calculate the drag coefficient for different shapes, specifically for a skydiver
  • Explore the effects of body position on terminal velocity in skydiving
  • Study the relationship between mass, weight, and terminal velocity in free fall scenarios
USEFUL FOR

This discussion is beneficial for physics students, educators, and anyone interested in understanding the dynamics of free fall and terminal velocity in skydiving scenarios.

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Homework Statement



A 79 kg skydiver can be modeled as a rectangular "box" with dimensions 25 cm x 39 cm x 1.8 m.

What is his terminal speed if he falls feet first?


Homework Equations







The Attempt at a Solution



So I am not sure what I am doing wrong, here is what i did.

D= 1/4 av2 = .25(.25 x .39)= .020

skydiver's weight i took from kg to N which ended up being 774.2

then i did 774.2/.020 and did square root, and i ended up with 196.7, apparently it is saying this is not the right answer, did i do this correctly!? help! :(
 
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What formula are you using? isn't the formula for drag [tex]\frac{1}{4}\rho ADv^2[/tex] maybe [tex]\frac{1}{2}\rho ADv^2[/tex] (Its late and I feel lazy to find out which)

where [tex]\rho[/tex] is the density of air, A is the area of the object and D is the coefficient of drag
 

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