Hello! i need a full answer on this one! this is due tomorrow and i really need to get it done!!!

The friction robs kinetic energy from the ball and turns it into heat energy.

Where does the heat energy go ? Both the ball and the floor get slightly warmer where they rub together.

Most times when this happens, the increases in temperature are pretty small and you can't feel them. But in other situations ... like rubbing two sticks together ... the temperature increases are certainly noticeable.  In fact, you can start  a campfire that way.

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.