Please check my physic problems!?

1. When a tuning fork is struck, it produces sound waves of wavelength 114 cm which travel at 343 m/s through air. What is the frequency of the tuning fork? My work: (1.14 / 343) = f f = .0033236 f = 3.33 x 10^-3 Hz *** my answer 2. A particle vibrates in Simple Harmonic Motion with amplitude. What will be its displacement in one time-period? **this one I don't understand at all. A 2A 4A 0 3. How will you find the height of a tall tower using a long-enough thread? You only have a stop-watch with you. So you can only measure time and not length. Explain the method by stating the formula you will use to calculate the height of the tower. My answer: h = (1/2)(g)(t^2)