Mort is on Earth, and Velma passes him at a high speed. Mort and Velma each carry a standard kilogram. Concerning the kilograms, Mort observes that
A) Velma's has a mass of 1 kilogram, but Mort's is less massive than 1 kilogram.
B) Velma's is less massive than 1 kilogram and Mort's has a mass of 1 kilogram.
C) Velma's is more massive than 1 kilogram and Mort's has a mass of 1 kilogram.
D) both have a mass of 1 kilogram.
E) Velma's has a mass of 1 kilogram, but Mort's is more massive than 1 kilogram.

Question

Quizplus · Accepted Answer

According to the theory of relativity, an object in motion relative to an observer will appear to have increased mass. Therefore, Mort observes Velma's kilogram as more massive than 1 kilogram, while his own remains 1 kilogram.

Mort Is on Earth, and Velma Passes Him at a High