Potential: If the electric potential at a point in space is zero, then the electric field at that point must be

Electric intensity will not necessarily be zero

Explanation:

E=−dV/dl

where E= Electric field intensity

V= Electric Potential ;

l= distance traveled in direction of electric field

Electric intensity at a point is the negative of rate of change of the electric potential at a point. So if a function is zero at a given point, the slope will not necessarily be zero at that point.

one person pulls 90n one way and the other has 100n pulling the other way.

so the net force = 90 - 100 = -10n,

or the ans can be 10n if the picture shows -90n and 100n instead.

continuous conducting path for current, power supply