Answer:
U = – 0.12J
Explanation:
Given N = 10 turns, I = 5A, r = 5×10-²m
B^ = 0.05 T iˆ+ 0.3 T kˆ
Magnitude of the magnetic field vector B = √(0.05²+0.3²) = 0.304T
Area = πr² = π(5×10-²)² = 7.85×10-³m²
Magnetic moment μ = NIA
μ = 10×5×7.85×10-³ = 0.3925Am²
U = -μ•B = –0.3925×0.304 = –0.12J
The sign is negative because the magnetic moment is aligned with the magnetic field.
Here we can say that there is no external torque on this system
So here we can say that angular momentum is conserved
so here we will have

now we have



similarly let the final distance is "r"
so now we have


now from above equation we have


so final distance is 0.04 m between them
Therefore as you move around the U.S. the acceleration due to gravity (g) varies from about 9.79 to 9.81 meters per second squared. The Earth’s average is 9.80 m/s2 which is generally reported as the acceleration of gravity on Earth.