Acollege friend of yours who has been postponing taking any science courses hears you talking about the generation of nuclear energy in the sun and makes the following observation: "the whole idea of the atomic nucleus is pretty ridiculous. if an oxygen nucleus consists of eight protons and eight neutrons, the charge on that nucleus is positive. since even i learned in high school that like charges repel, such a nucleus would find all its positive protons repelling and quickly fall apart." how would you answer his argument?

It's held together by the nuclear force.

Explanation:

There are more elemental forces than just the electromagnetic one. In this case, it is the nuclear force (called also strong force) the one that holds the nucleus together because it is stronger than the electromagnetic force over such short distances as the one inside the atomic nucleus.

they are playing too much beyblade in the office

explanation:

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.