Analytical Solution to the Falling Parachutist Problem
Problem Statement. A parachutist of mass 68.1 kg jumps out of a stationary hot air balloon. Use Eq. (1.10) to compute velocity prior to opening the chute. The drag coefficient is equal to 12.5 kg/s
The downward pull of gravity FD and the upward force of air resistance FU.
(It is a differential equation)
The exact solution as shown as follow,
Refer to the exact solution , we can write the Fortran code as follow,
program AS ! AS is program name
IMPLICIT NONE ! 關閉內定型態的功能, 每個變數必需事先宣告,位置在PROGRAM指令的下一行
REAL*8 m,g,c,v ! 宣告m,g,c,v為浮點數, REAL*4-浮點數單精度, REAL*8-雙精度浮點數
Integer*4 t ! 宣告t為長整數 – 使用4位元組（4 bytes, 32 bits）
OPEN(66, FILE=’AS.TXT’, STATUS=’UNKNOWN’)
Do t=0, 50, 1
WRITE(66 ,*) t, v
We can copy the results form AS.TXT to Excel, and present them to graphic diagram.
Numerical Methods for Engineers 6th P12-P15, Steven C. Chapra Raymond P. Canale