Rub your hands together vigorously. What happens? Discuss the energy transfers and transformations that take place.
Step 1 First, we should list out what all energies will be produced or transformed while rubbing the hands. They are, Kinetic Energy, K (Due to the relative motion of the hands) Gravitational Potential energy, U [It can g represented as “Potential energy” (U). But, it is purely due to gravitational force exerted So, it should be represented as Gravitational Potential Energy] Chemical energy, E (The energy which is spend by the body to move the hands) Ch Thermal energy, E (We feeTht as hot while rubbing the hands). Step 2 Here, we should analyse the possibilities of energy transformations which are mentioned above. 1. Chemical Energy (E ) Ch This energy is from our body and which will be converted to kinetic energy. 2. Kinetic energy (K) The chemical energy in our body will be converted to kinetic energy while rubbing 3. Gravitational potential energy (U ) g There is no change for the position of the hands and the Gravitational potential energy can be considered as zero. (If the change in position is high, then gravitational potential energy will come into the picture.) 4. Thermal energy (E ) Th The kinetic energy of hands generated from chemical energy of our body will be then converted to thermal energy.