University Physics Young and Freedman Chapter 21 Test your understanding questions and solutions Test your Understanding Chapter 21: Pre-chapter Question Q: Water makes life possible: the cells of your body could not function without the molecules dissolved in the water within the cells. What electrical properties of water make it such a good solvent? A: Water is polar and its positive and negative ends attract ions of the opposite charge, effectively separating them and keeping them in solution. 1. Strictly speaking, does the plastic rod in Fig. 21.1 weigh more, less, or the same after rubbing it with fur? What about the glass rod after rubbing it with silk? And what about the fur and the silk? A: With fur, rod takes on negative charge, so weighs more with addition of electrons. With glass, positive charge is taken on so weighs less with removal of electrons. Fur weighs less and glass weighs more for same reasons, respectively. 2.
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This note was uploaded on 04/18/2008 for the course PHYS 0030 taught by Professor Cutts during the Spring '07 term at Brown.