Well, for atoms to stop moving, the temperature would have to be at 0 K, aka absolute zero. However, that's theoretically impossible. Anyway, solid molecules barely move, "vibrating" against each other in a tightly packed space. For liquid molecules, they can slide past each other and move about, but there's not much space between the particles. As for gas, the particles are much faster than particles of solid or liquid, and the particles move about freely, bumping into each other.
The average speed of the particles in a substance is the definition of temperature.
The speed of which new particles form is called the rate of reaction.
The relative refractive index tells the speed of light in a vaccum over the speed of light in medium.
particles
No. Alpha particles are helium nuclei; such nuclei have a mass, and can therefore NOT travel at the speed of light.
No
Energy is lost. According to this the speed and direction would change
Speed must be specified relative to something. Relative to the Sun, the speed of Earth is about 30 km/second. Relative to the Milky Way, or relative to the Local Group, you would get different numbers.
Mass IS relative to the speed you are going.
The average speed of the particles in a substance is the definition of temperature.
Relative speed is the speed between two moving objects with no regards to a fixed reference. Speed is how fast something is moving with respect to an object.
Temperature is a measurement of the average speed of the particles in a substance.
Temperature is a measurement of the average speed of the particles in a substance.
Temperature is a measurement of the average speed of the particles in a substance.
Temperature is a measurement of the average speed of the particles in a substance.
Temperature is a measurement of the average speed of the particles in a substance.
Temperature is a measurement of the average speed of the particles in a substance.