In the late 17th century, Gottfried Leibniz proposed the idea of the Latin: vis viva, or living force, which defined as the product of the mass of an object and its velocity squared; he believed that total vis viva was conserved. To account for slowing due to friction, Leibniz theorized that thermal energy consisted of the random motion of the constituent parts of matter, a view shared by Isaac Newton, although it would be more than a century until this was generally accepted. The modern analog of this property, kinetic energy, differs from vis viva only by a factor of two.
Who proposed the idea of the Latin: vis viva?
Gottfried Leibniz

Neptune is similar in composition to Uranus, and both have compositions that differ from those of the larger gas giants, Jupiter and Saturn. Like Jupiter and Saturn, Neptune's atmosphere is composed primarily of hydrogen and helium, along with traces of hydrocarbons and possibly nitrogen, but contains a higher proportion of "ices" such as water, ammonia, and methane. However, its interior, like that of Uranus, is primarily composed of ices and rock, and hence Uranus and Neptune are normally considered "ice giants" to emphasise this distinction. Traces of methane in the outermost regions in part account for the planet's blue appearance.
What makes Neptune blue?
methane

The city has numerous neighborhoods consisting of vacant properties resulting in low inhabited density in those areas, stretching city services and infrastructure. These neighborhoods are concentrated in the northeast and on the city's fringes. A 2009 parcel survey found about a quarter of residential lots in the city to be undeveloped or vacant, and about 10% of the city's housing to be unoccupied. The survey also reported that most (86%) of the city's homes are in good condition with a minority (9%) in fair condition needing only minor repairs.
How many of Detroit's residential lots are are underdeveloped?
a quarter