One of the most fundamental concepts to understand in civil engineering is to understand the forces that act on objects.
A force is a vector, which means, it has both magnitude and direction. Vectors are shown with arrows, pointing in their proper direction, and, the size of the arrow in proportion to its magnitude.
Temperature for example is not a vector, because it only has magnitude. Speed is not a vector, it only has magnitude. But velocity for example, is a vector. It has both magnitude and direction. For example, we can show the velocity of a car moving at 50 km/h towards east, as an arrow pointing towards east, with a magnitude of 50 units on a scaled paper. A force is a vector. You can show the weight (which is a force) of a 10 pound glass full of water resting on a table as a 10 pound force directed downwards, towards the center of the earth, acting at the center of mass of the glass.
Statics, the most fundamental class in civil engineering, especially for structural but indirectly for other branches too, deals with forces when they act on bodies and the reactions they produce. In this we are not concerned yet about the strength of materials or how they deform (that will be done in next section). Here we simply analyze things from outside, and to the degree that we can solve with simple equations, and not advanced methods.
Now let’s introduce the essential concepts. I suggest pay as much attention as you can, if you are not an engineer, but as always, not understanding something in this post serries will not cause not understanding the rest of this post series, so if you are stuck after you spend reasonable attention, just keep going.
In the next post, we will introduce the term “Free Body Diagram”