An old mining tunnel disappears into a hillside. you would like to know how long the tunnel is, but it's too dangerous to go inside. recalling your recent physics class, you decide to try setting up standing-wave resonances inside the tunnel. using your subsonic amplifier and loudspeaker, you find resonances at 5.0 hz and 6.4 hz , and at no frequencies between these. it's rather chilly inside the tunnel, so you estimate the sound speed to be 331 m/s . based on your measurements, how far is it to the end of the tunnel?

Answertraveling around a circular trackexplanation"traveling around a circular track" is the best answer as you could be traveling around a circular track at a constant speed. your velocity would therefore have the same magnitude but will always be constantly direction. since acceleration is the rate of change of velocity, the rate of change will only involve the direction of velocity and not the magnitude.wrong choices: "an object at rest" does not accelerate at all"increasing speed while traveling around a curve" means that the acceleration will not be constant due to only change in direction; it will be constant due to both magnitude and direction"an object in free fall" does not necessarily change direction 

The fuzzy edges of shadows are a result of  diffraction