posted by Anonymous .
A uniform board is leaning against a smooth vertical wall. The board is at an angle above the horizontal ground. The coefficient of static friction between the ground and the lower end of the board is 0.750. Find the smallest value for the angle , such that the lower end of the board does not slide along the ground.
That would be zero, of course. Care to rephrase the question?
A pipe 0.42 m long and closed at one end is filled with an unknown gas. The third lowest harmonic frequency for the pipe is 780 Hz. (a) What is the speed of sound in the unknown gas? (b) What is the fundamental frequency for this pipe when it is filled with the unknown gas?