1. Why is the equivalent resistance in a parallel circuit equal to the sum of the reciprocals of the individual resistances, whereas in a series circuit, the equivalent resistance is the sum of the individual resistances? ​

ice to water 1 water to vapour 2 latent heat

it would be kevlar ^^

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.