How to consider stress analysis in physical mechanics of senior one

How to consider stress analysis in physical mechanics of senior one

Our teacher told the formula: gravity must have elasticity, look around (that is to see the analysis of the object and the outside world have a few contact points or surfaces, and then analyze) test: to see whether the force of the object is consistent with its state of motion. Use this formula to do a few questions, try it, slowly body will be able to do well!