<u><em>Diffusion:
</em></u><em> in diffusion particles move from area of higher concentration to the area of lower concentration..
</em><u><em>causes:
</em></u><em>the movement of particles allow them ti disperse,,, when molecules are close to each other they collide with each other and push each other apart so they spread in the whole area... :)</em><u><em>
</em></u>
Answer:
Gravity. It is the pull we feel. Neither motion could happen nor mass could keep us on the ground without the existence of gravity.
Answer:
Because the velocity v (As a Vector ) is going opposite direction ( -X axis ) .
Protons do not move out of the nucleus of atoms although they repel each other.
Remember that protons are particles with positive charge and they held together in the nucleus of the atom which is a tiny tiny region. As you know, like charges repel each other, which means that the protons exert a repulsion force.