Rock that become hot enough to melt and flow are referred to as blank by scientists

Lava

Explanation:

Heat at high temperature can cause rocks to melt into liquid form within the underground layer of the rocks. This molten rock trapped within is referred to as MAGMA. However, when this trapped molten magma begins to flow, it is said to be LAVA by scientists.

It is important to note that although magma and lava are both molten forms of rocks or a volcano, their differences lie in the fact that A LAVA IS AN ERUPTED or FLOWING MAGMA.

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.