Water flows up a plant's stem against the force of gravity. In which of the following ways could the movement of water up a plant be modeled? A. Place a clear pipe in a small tub of water. Shake the tub back and forth. Watch how the water moves around the pipe. B. Place the tip of a sponge in water dyed with food coloring. Watch how the water moves up the sponge. C. Pour a glass of water on top of a towel that is spread out on a table. D. Blow through a clear straw in a glass of water. Observe the level of water inside the straw.

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?