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Since you didn't say which ones I am going to start at the beginning, but assume you have some intuitive idea as to what is meant by a force, commonly stated as a push or a pull. This is a good start, about where Archimedes was coming from, but we need expanded detail for modern consideration. The weight of an object is a force. You can use that force to exert a push on something, by standing the object on it, say a brick on a table. Or a pull on that something by hanging the object from it, by a string, Or you can develop what is called a turning moment by pulling on one side or the other, tipping a wobbly table with a pile of bricks. This third use of a force is not often included in the popular definition, but we will use it later as it is very important in landslips and soil failures. Archimedes realised that the weight of an object is lessened by immersion in water, though it regains its original weight when removed from the water. He had discovered what we now call the bouyancy force, which acts against the weight force of the object itself. Though he didn't think of it in that way, in doing so he had discovered the idea of a net or resultant force. This is what happen when two or more forces act on the same body. I haven't the time tonight to do any sketches, so having set the scene I will continue tomorrow to extend Archimedes to Terzaghi's soil loading equation (Which is actually very simple). We have also found out that we need to know more about how to apply a force and I will address that which will lead to the idea of stresses and strains. How are we doing ? Meanwhile if you watch the BBC Devon local website there is a short but good video of a landslide that occurred last weekend near Teighmouth. https://www.bbc.co.uk/news/england/devon