The Sliding Ladder Problem

A ladder is leaning against a wall. The base of the ladder starts to slip[br]while the top of the ladder remains in contact with the wall. How does the rung [br]halfway up the ladder move in space as the ladder slips?[br][br]Can you prove your answer?[br][br]How do the other rungs move? What can you say about the path they[br]take as the ladder slips? Can you prove your answer?[br][br][i][b][size=85][Slide the base of the ladder by dragging the BLACK point. Slide the point whose path you [br]want to trace by sliding the RED point.][/size][/b][/i]

Information: The Sliding Ladder Problem