Consider two air-filled parallel-plate capacitors with circular plates. Capacitor 1 has a distance between plates d and plate radius R. Capacitor 2 has a distance between plates 2d and plate radius R/2.
If the capacitance of capacitor 1 is C, then the capacitance of capacitor 2 is?

1/8 x C

Explanation:

The capacitance of parallel plate capacitor

= ε₀ A /d where A is area of plate and d is distance between plate.

for capacitor 1

C =  ε₀ A /d

For capacitor 2

radius = R/2

Area = A / 4

Capacitance

= ε₀ (A/4) x ( 1 / 2d )

= ( 1 / 8) x (ε₀ A /d)

= 1/8 x C

i would think form in reponse to tensional forces

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.