How are nuclear reactions used to meet the world’s energy needs? Both fusion and fission are used to generate electricity, but more fission reactors than fusion reactors are in use.
Fission reactors are used to generate electricity, but fusion is not yet practical enough to be used.
Both fusion and fission are used to generate electricity, but more fusion reactors than fission reactors are in use.
Fusion reactors are used to generate electricity, but fission is not yet practical enough to be used.

Samir watches a 100-minute movie on his spaceship. maria's spaceshipe flies in the same direction as samir's spaceship but she observes his move to last 125 minutes and his spaceship to be 40 m long. how long does samir observe his own spaceship to be? according to an observer on earth, planet x is stationary. maria and samir depart earth on their spaceships at the same time, each flying at 0.5c. maria flies toward planet x and samir flies in the opposite direction. according to maria, her voyage to planet x takes 9 years. how many years does marias voyage take according to samir?