A moving object's mass is twice its rest mass. Its length (in the direction of travel) must therefore be
A) one-half its proper length.
B) twice its proper length.
C) one-fourth its proper length.
D) four times its proper length.
E) times its proper length.

Question

A moving object's mass is twice its rest mass. Its length (in the direction of travel) must therefore be
A) one-half its proper length. 
B) twice its proper length. 
C) one-fourth its proper length. 
D) four times its proper length. 
E) times its proper length.

Quizplus · Accepted Answer

The Answer of A moving object's mass is twice its rest mass. Its length (in the direction of travel) must therefore be
A) one-half its proper length. 
B) twice its proper length. 
C) one-fourth its proper length. 
D) four times its proper length. 
E) times its proper length.

A Moving Object's Mass Is Twice Its Rest Mass