Electromagnetic waves are often distinguished from mechanical waves. The distinction is based on the fact that electromagnetic waves .

can travel through materials and mechanical waves cannot

come in a range of frequencies and mechanical waves exist with only certain frequencies

can travel through a region void of matter and mechanical waves cannot

electromagnetic waves cannot transport energy and mechanical waves can transport energy

the correct one is the third :

can travel through a region void of matter and mechanical waves cannot

Explanation:

Mechanical waves travel supported by a material medium, for example sound waves travel in air, the wave on a string travels on the string.

Electromagnetic waves are produced by the variation of electric and magnetic fields, after producing this variation by the lenz law the variation of one field induces the other, so these waves do not need a material medium to travel.

Of the final statements the correct one is the third :

can travel through a region void of matter and mechanical waves cannot

the chart show the masses and velocities of two colliding objects that stick together after a collision.

according to the law of conservation of momentum, the momentum of the object after the collision is  

answer

1,500

kg • m/s.