【简答题】Stress is a normal physical response to things that make people feel worried or break their balance of life in some way. Stress isn’t always bad. Sometimes, people’s stress is important during emergen...
【单选题】If the normal stress on the cross section of the axial tensile rod is σ , then the normal stress and shear stress on the 45 ° degrees section are .
【简答题】Mr. Lee was in bed and was trying to go to sleep when he heard the bell ring. He turned on the light and looked at his clock. It was twelve o'clock. "Who can it be at this time of night?" He thought. ...