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
Feathers: The Evolution of a Natural Miracle "as synthesis goes, it is gracious, funny, persuasive and wide ranging." Peter Forbes, in a review published by "The Guardian", stated that Hanson's "enthusiasm is infectious", particularly for a topic Forbes found "alluring". "The Economist" published a review which also described Hanson as having "infectious enthusiasm" and stated, "Mr Hanson's unpretentious style makes what is essentially an excellent scientific work into an enjoyable read for the ignorant and uninitiated." Irene Wanner, in a review published by "The Seattle Times", highlighted Hanson's analogies, calling them "apt" and helping to "simplify complex concepts". "Kirkus Reviews" described "Feathers" as a "delightful ramble through