A120.0-v motor draws a current of 7.00 a when running at normal speed. the resistance of the armature wire is 0.720 ω. (a) determine the back emf generated by the motor. (b) what is the current at the instant when the motor is just turned on and has not begun to rotate? (c) what series resistance must be added to limit the starting current to 15.0 a?

This is for my 8th grade science class, i really don’t understand. can someone me? , lol.

Ascientific blank must be testable and capable of being proven false?

During the experiment if you could triple the breakaway magnetic force with all other quantities left unchanged, what is the new value for the critical velocity if it was v0 (initial velocity), initially? (b) now if you halved the radius with all other quantities left unchanged, what is the new critical velocity if it was v0 (initial velocity), initially? (c) if during the experiment, critical velocity quadrupled with all other quantities left unchanged, what is the new breakaway force if its magnitude was initially f0,?