What does question mark do in debug command?
How long does Pause 500 last?

Explain the difference laminar and turbulent flow. explain it with the shear stress and the velocity profiles.

What precautions should you take to prevent injuries when dealing with heavy loads?

Coiled springs ought to be very strong and stiff. si3n4 is a strong, stiff material. would you select this material for a spring? explain.