Answer:
William Gilbert
Explanation:
first described the Earth as a giant dipole magnet 400 years ago. But, as Rod Wilson recounts, he did far more than this.
Answer:
The average speed for the entire run is 12 km/h.
Explanation:
The average speed is given by the following equation:

Where:
: is the total distance
: is the total time
If during the first hour, they ran a total of 13 kilometers and then, they ran 5.0 kilometers during the next half an hour we have:


Hence, the average speed is:

Therefore, the average speed for the entire run is 12 km/h.
I hope it helps you!
Answer:
a. dW = ∫pEsinθdθ b. W = p.E
Explanation:
a. We know torque τ = p × E = pEsinθ where θ is the angle between p and E
Let the torque τ rotate the dipole by an amount dθ. So, the workdone dW = ∫τdθ = ∫pEsinθdθ
b. So, the total work done is gotten by integrating from 90 to θ. So,
W = ∫₉₀⁰dW
= ∫₉₀⁰pEsinθdθ
= pE∫₉₀⁰sinθdθ
= pE(cosθ - cos90)
=pEcosθ
= p.E
1 hour for the train to travel 17,000 feet