A train passes by a little boy at the depot. As it moves away from the boy at 65
m/s, the whistle emits a frequency of 4500hz.
What frequency does the little boy hear as
the train barrels off into the distance? The speed
of sound in air is 343m/s

Apossible explanation for a set of facts that can be tested by further investigation is called

Why are graphs useful when interpreting data

Light from a sodium lamp passes through a diffraction grating that has 1000 slits per millimeter. the interference pattern is viewed on a screen 1.000 m behind the grating. the first (m = 1) two bright yellow fringes that are visible are 0.7288 m and 0.7300 m from the central maximum. what are the wavelengths of these two fringes?