Hint We use the concept of gravitational potential energy to solve this question. Gravitational potential energy refers to the energy stored in an object as a result of its vertical position or height of elevation. With an increase in its height the potential energy increases. We see which of the cases in the options has the least height which will tell us the least potential energy.
Complete Step by step solution Any object can store energy based on its position. The stored energy in that position is potential energy. For example, when a drawn bow stores energy as a result of its position. When it is in its normal position that means when it is not drawn no energy is stored in the bow. But when its position is changed from its normal equilibrium position, it can store energy due to its position. In the case of gravitational potential energy. a relation between the height of an object and the gravitational potential energy is observed. The higher an object is elevated greater the gravitational potential energy of the object. From the options given a person sitting on a chair is most elevated. So, it has the highest potential energy. A person’s height from the ground is minimum when the person is sleeping or laying down in the ground. Hence the potential energy of a person is minimum when the person is sleeping on the ground.
Option (C) sleeping on the ground is the correct answer.
Note By this, we can say that the potential energy of a person increases while moving from the ground floor to the higher floor in a lift. When an object is dropped from a height the potential energy stored is converted into kinetic energy while in motion and when it reaches the ground the final energy becomes zero. This change in potential energy is equal to the kinetic energy and this is called conservation of energy.