Introducing viewpoints of mechanics into basic growth analysis - (I) three aspects of growth mechanics compared with three laws of motion

This study was conducted to analyze growth phenomena by introducing mechanical viewpoints into basic growth analysis. Relating weight (W), absolute growth rate (AGR) and growth acceleration (GA) suggested that (AGR) ² , which was described as the product of W and GA, looked like force involved in the growth of an animal or a plant. This might be due to the resemblance to the second law of Newton's three laws of motion, where the product of mass and acceleration is related with force to an object. If GA=0, then AGR=0. This caused the weight to stop changes and to keep the constant value with the passage of time, showing a resemblance to the law of inertia that is the first one of three laws of motion. AGR was obtained by extracting the square root of W·GA, taking both positive and negative values. Since AGR played the leading part in growth mechanics, W took both positive and negative values. The positive W was the weight of an animal or a plant, and in terms of it the negative W was assumed to be environmental substances from which an animal or a plant was constructed. If the positive AGR was the action of an animal or a plant on the environment, then the negative AGR was the reaction taken by the environment. The sum of positive AGR and negative AGR was equal to zero. This might show a resemblance to the law of action and reaction, the third one of three laws of motion. There were three aspects of growth mechanics that might be compared with Newton's three laws of motion.