1. The lowest key on a piano plays a note called A0 (27.5 Hz). If you push that key down very slowly and hold it, the felt hammer below won't have enough energy to strike the string but the wool damper, which usually rests on top of the string to stop it from vibrating, will stay lifted leaving the string "open." If you then play an A major chord one octave op, consisting of A1 (55 Hz) - C#2 (68.75 Hz) - E2 (82.5 Hz) - A2 (110 Hz), with a quick, hard strike and sudden staccato release, you will hear a soft, long-lived echo of the chord even though the dampers have stopped vibration in the strings of the chord. What is going on here? Explain in a few sentences. 2. Two children of unequal mass sit on a see-saw of length L. The lighter child sits at the end of her side, a length of L/2 from the axis of rotation. The heaver child sits halfway between his end and center, a length of L/4 from the axis of rotation. What is the ratio of their masses (light:heavy)? a) 1:1 b) 1:2 c) 1:3 d) 1:4

3. A small uniform disk (think cheese wheel) and a small uniform sphere (think lacrosse ball) of equal mass and radius are released simultaneously from the top of a high inclined plane (think soapbox derby), and they roll down without slipping. Which one will reach the bottom first? a) sphere b) disk c) they will reach the bottom at the same time d) it depends how steep the ramp is