Electromagnets can be turned off, this makes it easier to release things from the magnetic field.
Hope this helps :)
Compounds. two or more compounds.
Answer:
D Electromagnetic and gravitational
Answer:

Explanation:
For sound waves we have v=d/t where v is the speed of sound and d the distance between the astronauts, while for electromagnetic waves we have c=D/t where c is the speed of light and D the distance between the spaceship and Earth. <em>We have written both times as the same</em> because is what is imposed by the problem, so we have t=d/v=D/c, which means:

And for our values:
