Mechanical energy mechanical energy of the colliding objects has been converted into an equal amount of heat. Thus, the total energy of the system remains unchanged though the mechanical energy of the system has reduced. A satellite of mass formula_4 at a distance formula_5 from the centre of Earth possesses both kinetic energy, formula_6, (by virtue of its motion) and gravitational potential energy, formula_7, (by virtue of its position within the Earth’s gravitational field; Earth's mass is formula_8). Hence, mechanical energy formula_9 of a satellite is given by If the satellite is in circular orbit, the energy conservation equation can be further
Energy policy of China has the goal of achieving an integrated nationwide grid in the period between 2015 and 2020. In 2015, China generated 73% of its electricity from coal-fired power stations, which has been dropping from a peak of 81% in 2007. China is the world's leading renewable energy producer, with an installed capacity of 152 GW. China has been investing heavily in the renewable energy field in recent years. In 2007, the total renewable energy investment was $12 billion USD, second only to Germany. In 2012, China invested $65.1 billion USD in clean energy (20% more than in 2011), fully 30% of