Why does energy as heat move away from the tropics and toward the poles in the global weather system 1.There is less solar energy at the equator and more at the poles. 2.There is more solar energy at the equator and less at the poles. 3.The Earth’s poles attract energy as heat from the tropics because of gravity. 4.Energy as heat does not move away from the poles; rather, the sun heats all parts of the Earth evenly.

Uranium has two naturally occurring isotopes. 238u has a natural abundance of 99.3% and 235u has an abundance of 0.7%. it is the rarer 235u that is needed for nuclear reactors. the isotopes are separated by forming uranium hexafluoride uf6, which is a gas, then allowing it to diffuse through a series of porous membranes. 235uf6 has a slightly larger rms speed than 238uf6 and diffuses slightly faster. many repetitions of this procedure gradually separate the two isotopes. what is the ratio of the rms speed of 235uf6 to that of 238uf6? express your answer to five significant figures.