Como parte de su experimento de feria
científica, María seleccionó un método de
separación que le permitió descomponer el
agua de una muestra.
¿Cuál método de separación experimental
usó María para descomponer las
moléculas de agua?

A .Calentó el agua hasta que se evaporó.

B. Filtró el agua varias veces usando
algodón

C. Aplicó una corriente eléctrica al agua que
quería separar

D. Colocó el agua en una centrífuga con
movimiento constante de rotación veloz.

When a book falls from a shelf to the ground without anyone pushing on it, no work is done on the book. true or false

Comedians like to joke that the reason we haven’t been visited by intelligent life from elsewhere in the universe is that aliens have been monitoring earth’s broadcasts of intellectually embarrassing tv programs, like gilligan’s island, fear factor, the jersey shore, and the jerry springer showand so consider us far too primitive to merit a visit. let’s check the assertion that aliens could have been receiving them. tv programs are broadcast at a frequency of about 100mhz with about 100kw of total power in 30frames per second, which emanatesroughly uniformly in all directions. assume that interstellar space transmits these broadcasts without attenuation. no matter how smart they are, aliens would require at least one photon per frame to interpret our signals. findthe number of photons per unit time per unit area reaching a receiver on a possible planet in the nearest star system, which is about 4 light-years away (a light-year is the distance light travels in a year). if aliens aimed a receiver or detector directly at earth, how big (in diameter) would it have to be to receive a photon per frame

Afeather of mass 0.001 kg falls from a height of 2 m. under realistic conditions, it experiences air resistance. based on what you know about friction, what can you say about the kinetic energy of the feather as it reaches the ground? acceleration due to gravity is g = 9.8 m/s2. a. ke < 0.0196 j b. ke = 00196 j c. je = 0 j d. ke > 0.0196 j