Electrical energy - The communication of neurons with each other takes place at synapses. Synapses are of two types i.e. chemical and electrical. A signal transduction process by a neuron uses electrical energy. In electrical synapse, flow of ions between cells takes place.
Gravitational potential energy - It is the energy possessed by an object when it is placed at some height. It is given by :
PE = mgh
The energy used when "a ball is at the top of a hill" is gravitational potential energy.
Mechanical energy - It is the total energy i.e. it is the combination of gravitational potential energy and kinetic energy.
The flexing of an arm muscle is an example of mechanical energy.
