Understanding Structural Engineering 

I will try my best

Thank you very much for your kind words. Have a wonderful day.

Thank you for watching and for your kind words! I'm glad you found the class helpful. If you have any additional questions or would like to learn more about reinforcement in concrete or other structural engineering topics, feel free to reach out. I'm always happy to help out and share my knowledge. Thank you again for your support and I hope you have a great day!

simple answer is force vs mass. material strengths consider the relationship between stress and deflection. there are many different material strengths that can be considered in the design process; such as load strength, fatigue strength, yield strength, etc. we see failure when the stress on the component is greater than the material strength. force in this case is mass (kg) * gravity (m/s^2). the newton unit is (kg*m)/(s^2); so kN/(mm^2) is the stress, which is the force due to the weight (m*g) over an area. this can be confusing as the units of force in the English system is in lbf while the mass unit is lbm; but both are commonly just called pounds. hope this helps.