Afreight train rolls along a track with considerable momentum. if it rolls at the same speed but hastwice as much mass, its momentum is
a. zero. b. doubled. c. quadrupled. d. unchanged.

b. doubled

Explanation:

The momentum of an object is given by

where

m is the object's mass

v is its velocity

We see that the momentum is directly proportional to mass. Therefore if the speed of the object is unchanged, but the mass is doubled: m' = 2m, the new momentum will be

so the momentum is doubled.

it may be wrong but i think its a

b.

hope this : )