A helical compression spring has a scale of 400lbs/in, an inside diameter of 2.25 inches, a free length of 8 inches, and squared and ground ends. The material is to be chrome vanadium steel. For a load, P, of 750 pounds and for average service,
determine:
1. Standard-size wire diameter.
2. Number of active coils.
3. The solid height.
4. The stress at a solid height.