Lectures on Physics has been derived from Benjamin Crowell's Light and Matter series of free introductory textbooks on physics. See the editorial for more information....

You take the high road and I’ll take the low road

Example 5

The figure shows two ramps which two balls will roll down. Compare their final speeds, when they reach point B. Assume friction is negligible.

Each ball loses some energy because of its decreasing height above the earth, and conservation of energy says that it must gain an equal amount of energy of motion (minus a little heat created by friction). The balls lose the same amount of height, so their final speeds must be equal.

Last Update: 2009-06-21