If you wrap some of the wire around the nail in one direction and some of the wire in the other direction, the magnetic fields from the different sections fight each other and cancel out, reducing the strength of your magnet.
At point C because it is at the lowest position.
Here if we assume that there is no air friction on both balls then we can say

now the acceleration is given as


so here both the balls will have same acceleration irrespective of size and mass
so we can say that to find out the time of fall of ball we can use


now from above equation we can say that time taken to hit the ground will be same for both balls and it is irrespective of its mass and size
Answer:
magnitude of A − B = 15.81 km
Explanation:
Vector A points in the negative y-direction and has a magnitude of 5 km. Vector B points in the positive x-direction and has a magnitude of 15 km.
According to Cartesian coordinate system, the resultant will start either from tail of A and ends at head of B and vice-versa.
A(0,-5)
B(15,0)
A - B = (-15 i - 5 j )
Magnitude of the vector is given by
|A - B| = 
|A - B| = 
|A - B| = 15.81 km