Almost 79% of the earth’s atmosphere is composed of
a. nitrogen
b. oxygen
c. helium
d. carbon dioxide

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?

Use the right-hand rule for magnetic force to determine the charge on the moving particle. this is a charge.

Sort the images based on whether there's a force of attraction or repulsion between the magnets shown. attraction repulsion