1 F 1 chons two dentical razor bladenAana Broposate building 4 m high Blade Als dropped on its face while blade is dropped on its edge av blade A blade B Fig. 1.3 (a) State the force which pulls the blades down. timos potential force​

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.