A relaxed spring of length 0.16 m stands vertically on the floor; its stiffness is 1020 N/m. You release a block of mass 0.5 kg from rest, with the bottom of the block 0.5 m above the floor and straight above the spring. How long is the spring when the block comes momentarily to rest on the compressed spring

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.

the rearrangement of particles in a physical change. hope this