An ion has unequal numbers of which two particles A)protons and electrons orbit shells B)neutrons and electrons C)protons and neutrons D)electrons and protons

Aspacecraft that renters the earth’s atmosphere drastically slows down. the amount of kinetic energy the spacecraft has as it reenters the earths atmosphere

What is the name of the perceived change in a sound wave’s frequency due to motion between the observer and the sound source?

The path of a satellite orbiting the earth causes it to pass directly over two tracking stations a and b, which are 51 miles apart. when the satellite is on one side of the two stations, the angles of elevation at a and b are measured to be 87 degrees and 84 degrees, respectively. (a) how far is the satellite from station a? (b) how high is the satellite above the ground?