Which of the following is made up of vibrating electric and magnetic fields traveling together?
A. An electromagnetic wave
B. A generator
C. An induced current
D. An electromagnet

the second one and the forth one are in the purple because they are opinions and the rest are in the yellow

explanation:

1/0.14nm = 10^10/1.4 a lot

the box does not move because you need to use a force greater than 300 n. you are only using 50 n. it needs to at least be 301 n for the box to move because then it is an unbalanced force and it will move the way that the greater force is pushing it. if you use only 300 n it will be a balanced force and will not move because the force you are exerting on the   box is the same as its force.

hope this !

im sorry if i went too in depth, i am going to include a link to a video on khan academy that will explain this.   hope that you like the video and that it explains more in detail to you.

that is the link.