The gas pressure inside a piston-cylinder device is initially balanced by atmospheric pressure. The initial pressure is 100 kPa and volume of the gas in the cylinder is 32 cm3. A spring attached to the outside of the piston exerts no force on the piston. The area of the piston is 0.0004 m2. Heat transfer to the gas causes the piston to move upwards by a distance of 2 cm. The spring constant is 10 N/cm. (a) Determine the final absolute pressure (kPa) of the gas. (b) Calculate the final volume (cm3 ) of the gas. (c) Show the expansion process on a P-V diag

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.