Answer:
Explanation:
Distance divided by time gives average speed.
And return to their normal position after the wave passes.
Answer:
See explanation.
Explanation:
If both stars explode in simultaneously in the <em>your </em>frame of reference then obviously you will see the two flashes simultaneously, and therefore, the time difference between the events would be zero.
If however, the stars exploded simultaneously in their frame of reference, then you would not observe the flashes simultaneously. Then the time difference between the events will not be zero, rather, you will observe star B exploding first and star A after.
The answer is C. an electron in an orbit has a fixed energy.