Calculating Terminal Speed of a 82kg Skydiver using Basic Physics Formulas

In summary, the question is about a skydiver who can be modeled as a rectangular "box" with dimensions 21cm× 44cm× 1.8m and the goal is to calculate their velocity using the given formula. However, the initial attempt at a solution was incorrect and the reason for this is unclear as the question does not specify if the skydiver dives head first or legs first. It is also suggested to take the largest surface of the box as the area in order to get a more accurate result.
  • #1
Steelers72
30
0

Homework Statement


A 82kg skydiver can be modeled as a rectangular "box" with dimensions 21cm× 44cm× 1.8m

Homework Equations


v = sqrt(2mg/(rho * C *A))

The Attempt at a Solution



A = 0.21 m * 0.44 m = 0.0924 m^2

v = sqrt(2 * 82 kg * 9.81 m/s^2 / (1.2 kg/m^2 * 0.0924 m^2 * 0.80))
=135m/sApparently this is wrong. I have tried many other formulae but I haven't had luck and I have one more attempt remaining. Any ideas?
 
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  • #2
Why are you assuming that he dives "head first"?
 
  • #3
Svein said:
Why are you assuming that he dives "head first"?

the question doesn't suggest otherwise, doesn't specify if he dives head first or legs first.
 
  • #4
Steelers72 said:
the question doesn't suggest otherwise, doesn't specify if he dives head first or legs first.

What if the skydiver takes this attitude, before the parachute opens?

freefall2.jpg
 
  • #5
SteamKing said:
What if the skydiver takes this attitude, before the parachute opens?

freefall2.jpg

Agreed! Take the largest surface of the box as area.
 

FAQ: Calculating Terminal Speed of a 82kg Skydiver using Basic Physics Formulas

1. What is terminal speed?

Terminal speed, also known as terminal velocity, is the maximum velocity that an object can reach when falling through a fluid, such as air or water. It occurs when the upward force of air resistance is equal to the downward force of gravity, resulting in a constant velocity.

2. How is terminal speed calculated?

Terminal speed can be calculated using the formula Vt = √(2mg/ρAC), where Vt is terminal speed, m is the mass of the object, g is the acceleration due to gravity, ρ is the density of the fluid, A is the cross-sectional area of the object, and C is the drag coefficient.

3. What factors affect terminal speed?

The factors that affect terminal speed are the mass and shape of the object, the density and viscosity of the fluid, and the gravitational pull. Objects with a larger mass or a larger surface area will have a higher terminal speed, while a denser or more viscous fluid will decrease the terminal speed.

4. Can terminal speed be exceeded?

In a fluid medium, terminal speed is the maximum speed that an object can reach. However, in a vacuum, there is no air resistance, so an object will continue to accelerate until it reaches its maximum speed, also known as its escape velocity.

5. How is terminal speed different from freefall?

In freefall, an object is accelerating due to the force of gravity. However, in terminal speed, the object has reached its maximum velocity and is no longer accelerating. In freefall, an object will continue to accelerate until it reaches the ground, while an object at terminal speed will maintain a constant velocity.

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