Answer:
Being in an accelerated frame is indistinguishable from experiencing gravity.
Step-by-step explanation:
The general theory of relativity is the geometric theory of gravitation that describes it in modern physics. It generalizes the gravity as a geometric property of the space and time, or spacetime.
One of the principles of this theory is the equivalence principle, which states that the gravitational force experienced at a stade mode have no difference of the pseudo-gravity experienced in an accelerated frame, if the referential is a massive body, such as Earth.
Mass is not equivalent to weight, because weight is a force, which is the mass multiplied by the gravity acceleration; the other two statements come from Newton's gravitational theory.