Answer:
Third Option

Explanation:
If we have a vector A = ax + by we know that by definition
cA = cax + cby
Where c is a constant.
In this case we have two vectors

You may notice that vector B has an opposite direction to vector A.
You may also notice that | Ax | is the double of | Bx | and | Ay | is double of |By |
That is to say

So the equation that relates to vectors A and B is:
.
You can verify this relationship by performing the operation


An asteroid in the asteroid belt
Formula from physics to get the answer.
Answer:
a. The thickness of the wire is 2.5 mm.
b. The wire is 0.25 cm thick.
Explanation:
Number of turns of the wire = 10
The length of total turns = 25 mm
a. The thickness of the wire can be determined by;
thickness of the wire = 
= 
= 2.5 mm
Therefore, the wire is 2.5 mm thick.
b. To determine the thickness of the wire in centimetre;
10 mm = 1 cm
So that,
2.5 mm = x
x = 
= 0.25 cm
The wire is 0.25 cm thick.