The motion of a skateboarder along a horizontal axis is observed for 5 seconds. the initial position of the skateboarder is negative with respect to the origin, and its velocity throughout the 5 seconds is also negative. at the end of the 5 seconds, is the skateboarder closer to or further from the origin (compared to where it started)?
why? explain.

When the warmer parts go up and the colder parts go down in a circular motion. 

An em wave does not require a medium, while a mechanical wave does. 

Jenny and fred both play a long note on their trombones. a stationary observer hears the sound increasing and decreasing repeatedly in loudness. which of these must be true? the sound waves from the two trombones have slightly different frequencies.the sound waves from the two trombones have the same frequency.the sound waves from the two trombones have slightly different amplitudes.the sound waves from the two trombones have the same wavelength.the sound waves from the two trombones have slightly different velocities.  lolthe answer is          the sound waves from the two trombones have slightly different frequencies.