In a closed glass tank which is filled with water to the brim, there are two spheres, one of cork and one of lead. The cork sphere is fixed to the bottom by a thread to prevent it from rising further; the lead sphere hangs from a thread fixed to the top of the tank. The lengths of the threads are such that the lead sphere is hanging just above the cork sphere. Explain what happens from the point of view relative to the tank and from the point of view relative to the Earth, if the tank is now suddenly moved to the right.

           __________________
          |        |         |
          |========|=========|
          |========|=========|
          |========|=========|
          |========O=========|  <----- lead sphere
          |==================|
          |========O=========|  <----- cork sphere
          |========|=========|
          |========|=========|
          |========|=========|
          |________|_________|

Ever fill up a glass bottle completely with water and koolaid mix and sugar and then cap it so there is no air,  then try to shake it.  Nothing mixes any faster, unless there was air in the container, or you spun the container (friction against the wall).  Water wont compress...... so....the two balls would do nothing, they would stay in their same location relative to the container.  If you tipped the container, then they would move in opposite directions

Posted by Jim on 2006-01-06 23:29:36