What is velocity and tell me the importance of velocity in physics

The extremely high temperatures needed to trigger nuclear fusion are proposed to be generated by laser irradiating a spherical pellet of deuterium and tritium fuel of diameter 1.8 mm. (a) determine the maximum fuel temperature that can be achieved by irradiating the pellet with 200 lasers, each producing a power of 550 w. the pellet has an absorptivity 0.3 and emissivity 0.8.

What do elements in a family tend to share. a.) similar periods b.) similar groups c.) similar atomic symbols d.) similar chemical properties and characteristics

Which is not an example of how an object gains elastic potential energy by stretching? a. jumping on a pogo stick b. pulling on a rubber band c. jumping on a trampoline