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.

It's a snowy day and you're pulling a friend along a level road on a sled. you've both been taking physics, so she asks what you think the coefficient of friction between the sled and the snow is. you've been walking at a steady 1.5m/s, and the rope pulls up on the sled at a 32 ∘ angle. you estimate that the mass of the sled, with your friend on it, is 65 kg and that you're pulling with a force of 80 n .