The graph above, which we discussed in class, shows the relativity of time, space, and mass [you will need to figure out which graph goes with which effect]. As measured by Velma, her spaceship has a mass of 10,000 kg and a length of 100 m. She moves at 80% of lightspeed relative to Mort. According to Mort's measurements, the mass and the length of her spaceship are
A) 6000 kg and 60 m.
B) 16,500 kg and 60 m.
C) 6000 kg and 165 m.
D) 16,500 kg and 165 m.
E) This question cannot be answered without knowing which observer is really at rest.

Question

Quizplus · Accepted Answer

According to the theory of relativity, as Velma's spaceship moves at 80% of the speed of light relative to Mort, Mort will measure the spaceship's mass as increased (relativistic mass increase) and its length as contracted (length contraction). The relativistic mass is calculated using the formula $ m' = \frac{m}{\sqrt{1 - v^2/c^2}} $, and the length is calculated using $ L' = L \sqrt{1 - v^2/c^2} $. For 80% of lightspeed, the mass increases to 16,500 kg and the length contracts to 60 m.

The Graph Above, Which We Discussed in Class, Shows the Relativity