Q019) Radiometric dating of a magnetic anomaly stripe of rock that is 225 km away from the mid-ocean ridge axis gives an age of 4.5 million years. Assuming a constant rate, seafloor spreading in this area occurs at a rate of a. 50 km per year. b. 5 cm per year. c. 20,000 cm per year. d. 1,012.5 km per year.

i think the answer is a, hope this is right, that would be my best guess.

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.