Calculating Maximum Deceleration of Re-entry Capsule

[spacemike1]

Homework Statement

Contact lenses being manufactured in space are returned in a re-entry capsule to Earth for distribution and sale. If the re-entry velocity is 7.4km/s and the re-entry flight-path angle is 10 degrees, determine the maximum deceleration it will experience and at what altitude? The capsule’s BC is 1000 kg/m^2

Homework Equations

a max = V^2 re-entry b sin y/ 2e

The Attempt at a Solution

a max = 7400m/s^2 (0.000139m^-1 sin(10)) / 2(2.7182)

the answer should be 24.813 , I keep getting a very high number of 9.298x10^10 ... why am I so off?

where .000139m^-1 is the atmospheric scale height and 2.7182 is the base of the natural logarithm.

 

[gneill]

When I run the same numbers I get 243.122 m/s^2

Where does the BC number figure into the problem?

 

[spacemike1]

the BC number is actually for the second part of the question. You got closer to me. I tried my calcs again and still getting the same off-base number. I've plugged it into the calculator just like this.

7400^2 (0.000139m^-1 sin(10)) / 2(2.7182) and get 9.298x10^10

 

[D H]

You apparently are dividing by 0.000139m^-1.

 

[gneill]

You apparently are dividing by 0.000139m^-1.

...and multiplying by e.