A standing wave is set up in a pipe with both ends open. The frequency of its first harmonic is 300 Hz. What is the length of the pipe? Take the speed of sound to be 340 m s–1. Give your answer in meters.

Aball is fired with an initial velocity of 500 m/s at an angle of 30 degrees above the horizontal across a level field. a. what are the horizontal and vertical components of the initial velocity. b. calculate the maximum height, the time of flight, and the range of the ball.