**Sample Problem 7-6a**
The work done by the gravity during the fall is 5.880000e+004J

**Sample Problem 7-6b**
The work done by the tension is -4.704000e+004J

*Sample Problem 7-6c**
The net work done is 1.176000e+004J

**Sample Problem 7-6d**
The final kinetic energy of the cab is 1.576000e+004J