Answer:
Velocity
Explanation:
Objects in motion usually have a speed which is scalar or velocity which is a vector.
A scalar quantity is one with magnitude but has no directional attribute.
A vector quantity is one with both magnitude and directional attribute.
Speed is a scalar quantity that describes the magnitude of motion a body accrues.
Velocity is a vector quantity that describes both the magnitude of motion and the direction of motion in a body.
they are made up of rock and gas
This looks like the photo electric effect ... classical physics reckoned that if you shone an intense enough light beam on a metal you could get electrons ejected from the metal (maybe in analogy to thermionic emission - heat). It sort of "forgot" about the frequency and photon/particle nature of light.
Enter the "photo electric" effect experiment, Einstein's explanation, and the Nobel committee having an excuse to award E a Nobel prize, even though said prize was probably more for relativity.
