An elevator of mass 15kg is suspended from a cable. A 402N force of tension pulls upward on the elevator to accelerate it upward. What is the magnitude of the upward acceleration of the elevator.

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 maria's voyage take according to samir?