We know how to handle stress and strain in a relationship. We have significant figures. The motion of rigid bodies.
Engineers do it to specification.
According to Newton, if two bodies interact, their forces are equal and opposite. We know it's not the length of the vector that counts, but how you apply the force. I've come a long, long way she said, and I will go as far, With the man who takes me from this horse and leads me to the bar. The men who took her from her steed and stood her to a beer, Were a bleary-eyed Surveyor and a drunken Engineer. The Engineer was busy doing research after dark, His scientific method was a marvel to observe, While his right hand write the figures, his left hand traced the curves.