The term yardstick refers to what is a normal response. It really has nothing to do with a yardstick and can be used in many situations. A yardstick is a measurement that has been tested over and over and than that measurement becomes the standard.
Say the yardstick for a reaction time is 5 seconds
Meaning that is what a normal healthy person can do it in.
Joan has the reaction in 4.8 second. Well she is on the the bell curve and did better than the yardstick test measure.

⇰Let O be the point of observation on the ground OX.
⇰Let A and B be the two positions of the jet.

















![\bf[ \boxed{➯OM=OL+LM=OL+AB=(x+3000)m \: and \: BM=h \: m]}](https://tex.z-dn.net/?f=%20%5Cbf%5B%20%5Cboxed%7B%E2%9E%AFOM%3DOL%2BLM%3DOL%2BAB%3D%28x%2B3000%29m%20%20%5C%3A%20and%20%5C%3A%20BM%3Dh%20%5C%3A%20m%5D%7D)


⇰ Equating the value of x from (1) and (2),we get;





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All living organisms carried out metabolism. Metabolism refers to a set of biochemical reactions on which the survival of the living organisms depend. Living organisms get energy from the food they eat to fuel the biochemical reactions. The majority of the energy needed in the body is derived from carbohydrates. When carbohydrate is eaten, it is broken down through the metabolic process of glycolysis and subsequent biochemical reactions and the final product is energy. This energy is then used for various purposes in the cell, especially to drive biochemical reactions and it can be transferred from one form to another.<span />