Question

Descirbe what energy transformations and/or transfers are occuring in the following activities. Add enough detail to justify your answer.

A) Chemical energy to thermal energy followed by work done.

B) Kinetic energy to potential energy with no change in thermal energy.

Answer 1

A) According to first law of thermodynamics energy can neither be created nor be destroyed but can be converted from one form to other. Now when chemical energy is changing into thermal energy, it is actually internal energy associated with atomic bonds of the molecule is changing. During chemical reactions such as combustion of gasoline some chemical some chemical bonds are destoryed while other are formed resulting in production of thermal energy. Thermal energy is due to high motion of molecutes possessing large kinetic energy and is proportional to temperature. A part of this energy can be converted into useful work called work done. The example of vehicle engine can be used to appreciate this, where chemical energy of gas gets converted to thermal engery and part of thermal energy is converted to useful work done.

B) Kinetic energy and potential energy are macroscopic form of engergy. Kinetic energy of the object is organised form of energy associated with motion of molecules in one direction. or around an axis. While potential energy is due to location of the object above or below the datum. Example for appreciation can be taken of a spring mass system used in suspension of the vehicles, where kinetic energy of chasis of the vehicle is converting to potential energy of spring suspension and producing negligible thermal energy.