A boat turns off its engine while traveling at 10 m/s, and then a constant drag force slows the boat to a stop, while traveling an additional 80 m. The mass of the boat is 600 kg . What is the magnitude of the constant drag force, in Newtons, required to stop the boat in 80 m?

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.

answerdmitry mendeleyev made a workable classification of the elements