Asolenoidal coil with 25 turns of wire is wound tightly around another coil with 310 turns. the inner solenoid is 25.0 cm long and has a diameter of 2.00 cm. at a certain time, the current in the inner solenoid is 0.116 a and is increasing at a rate of 1.85 103 a/s. (a) for this time, calculate the average magnetic flux through each turn of the inner solenoid. wb (b) for this time, calculate the mutual inductance of the two solenoids. h (c) for this time, calculate the emf induced in the outer solenoid by the changing current in the inner solenoid. v

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.