Please help me please

Trumpeter a holds a b-flat note on the trumpet for a long time. person c is running towards the trumpeter at a constant velocity. person b is running away from the trumpeter at the same rate. person d is standing still the whole time. which person hears a frequency that is lower than the b-flat?

Explain what it means to view something from a frame of reference. provide an example that illustrates your explanation. (4 points)

Steel water aluminum think about the three words listed here. which word could be added as the title of this list of words to tell how these words are related? a) conductors b) heat c) insulators d) metals