The difference between visible light and X rays is that a. the speed of X rays is greater.
b. they travel through a different medium.
c. the amplitude of visible light is greater.
d. the frequency of X rays is greater.

If two students are running down the hall toward each other, trying to get to class, and they have the same mass and acceleration, what will happen when they collide? will their forces cancel out or will each one experience a reaction?