What happens to the density of an object as it moves with respect to you as compared with the same object at rest with respect to you?

Question

Quizplus · Accepted Answer

According to the theory of relativity, as an object moves relative to an observer, its length contracts in the direction of motion (length contraction), while its mass increases (relativistic mass increase). Since density is mass per unit volume, and volume decreases due to length contraction, the density of the object increases.

What Happens to the Density of an Object as It