What energy keeps the water cycle going? Evaporation powers the water cycle because the vapor rises up to the clouds and condenses.
The wind's energy blows the clouds around the earth's atmosphere and causes the water cycle.
The air's energy cools water vapor, condensation occurs, and precipitation falls.
The sun's energy heats the earth's surface causing water to heat and evaporate.

An alpha particle with kinetic energy 12.5 mev makes a collision with lead nucleus, but it is not "aimed" at the center of the lead nucleus, and has an initial nonzero angular momentum (with respect to the stationary lead nucleus) of magnitude l = p0 b, where p0 is the magnitude of the initial momentum of the alpha particle and b=1.40×10−12 m. (assume that the lead nucleus remains stationary and that it may be treated as a point charge. the atomic number of lead is 82. the alpha particle is a helium nucleus, with atomic number 2.) what is the distance of closest approach?