POSSIBLE POINTS: Which distance can be most accurately measured with a meter stick?
The length of a river
The width of a book
The distance between two cities
The size of an object under a microscope

Width of a book

Explanation:

A river is much wider than a meter (3’3”)

Width of a book will be a few inches to no more than a couple feet.

The distance between cities is hundreds and hundreds of meters.

A microscope is less than a couple inches.

fgravity=10x10=100n case 1

fgravity=30x20=600n case 2

6 times more

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.