Explain the following: (a) An object increases its energy when raised through a height. (b) Energy is neither created nor destroyed then from where dowe get energy. (c) When we push the wall, the wall does not move and no work is done.
(a) An object has some mass 'M, when it is raised through a certain height, energy is applied on it, this energy gets transformed and is gained by the object hence its potential energy increases. (b) Energy is present in every object in some or other form. It exist in sun, planet, wind, water etc, the energy gets transformed and we get, because of its transformation into different form. For e.g., sun energy —> plants convert it (due to chemical reaction) into food energy →→ we eat green vegetables products of plants, energy enters our body. (c) Work is said to be done, when force is applied on the body and it moves to certain distance. When a wall is pushed there is no displacement and we say that work done is zero.
