Corrected entry: When the Rangers get into the cave for first time they are soaked, but when they speak with Zordon they are dry.
Corrected entry: If the Power Rangers have the power of super strength then how come it takes all four of them to carry Billy back to the headquarters after Rita kills him?
Correction: It doesn't. They chose to share the duty out of respect, like pallbearers.
Corrected entry: It's unbelievable that Trini survived when she fell from the top of the cliff.
Correction: She fell into water. The height of the fall is never shown so we can't really speculate how far down it was, but it's very reasonable that the water broke her fall without hurting her.
Correction: The water could be some kind of an illusion. From the moment they land out of the water, they never appear fully wet aside from their heads and hair which gradually dry.