Remember Coulomb's law: the magnitude of the electric force F between two stationary charges q₁ and q₂ over a distance r is

where k ≈ 8,98 × 10⁹ kg•m³/(s²•C²) is Coulomb's constant.
8.1. The diagram is simple, since only two forces are involved. The particle at Q₂ feels a force to the left due to the particle at Q₁ and a downward force due to the particle at Q₃.
8.2. First convert everything to base SI units:
0,02 µC = 0,02 × 10⁻⁶ C = 2 × 10⁻⁸ C
0,03 µC = 3 × 10⁻⁸ C
0,04 µC = 4 × 10⁻⁸ C
300 mm = 300 × 10⁻³ m = 0,3 m
600 mm = 0,6 m
Force due to Q₁ :

Force due to Q₃ :

8.3. The net force on the particle at Q₂ is the vector

Its magnitude is

and makes an angle θ with the positive horizontal axis (pointing to the right) such that

where we subtract 180° because
terminates in the third quadrant, but the inverse tangent function can only return angles between -90° and 90°. We use the fact that tan(x) has a period of 180° to get the angle that ends in the right quadrant.
Answer:........u are so sweet
Answer:

Explanation:
From the question we are told that:
Number of turns 

Conductor each with side length 
Current 
Magnetic field
Generally the equation for the total magnetic moment M is mathematically given by



Average speed = (total distance) / (total time)
Average speed = (4+7+1+2 blox) / (1 hour)
<em>Average speed = 14 blocks/hour</em>
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I'm gonna go out on a limb here and take a wild guess:
I'm guessing that there's another question glued onto the end of this one, and it asks you to find either her displacement or her average velocity. I'm so sure of this that I'm gonna give you the solution for that too. If there's no more question, then you won't need this, and you can just discard it. I won't mind.
Average velocity = (displacement) / (time for the displacement)
"Displacement" = distance and direction from the start point to the end point, regardless of how she got there.
Displacement = (4E + 7W + 1E + 2W)
Displacement = (5E + 9W)
<em>Displacement = 4 blocks west</em>
Average velocity = (4 blocks west) / (1 hour)
<em>Average velocity = 4 blocks/hour West</em>