<u>A</u> would be the answer, since it would take about 3 hours to cover most of it, 10km/h would be the average speed.
really hope this helps.
The H field is in units of amps/meter. It is sometimes called the auxiliary field. It describes the strength (or intensity) of a magnetic field. The B field is the magnetic flux density. It tells us how dense the field is. If you think about a magnetic field as a collection of magnetic field lines, the B field tells us how closely they are spaced together. These lines (flux linkages) are measured in a unit called a Weber (Wb). This is the analog to the electric charge, the Coulomb. Just like electric flux density (the D field, given by D=εE) is Coulombs/m², The B field is given by Wb/m², or Tesla. The B field is defined to be μH, in a similar way the D field is defined. Thus B is material dependent. If you expose a piece of iron (large μ) to an H field, the magnetic moments (atoms) inside will align in the field and amplify it. This is why we use iron cores in electromagnets and transformers.
So if you need to measure how much flux goes through a loop, you need the flux density times the area of the loop Φ=BA. The units work out like
Φ=[Wb/m²][m²]=[Wb], which is really just the amount of flux. The H field alone can't tell you this because without μ, we don't know the "number of field" lines that were caused in the material (even in vacuum) by that H field. And the flux cares about the number of lines, not the field intensity.
I'm way into magnetic fields, my PhD research is in this area so I could go on forever. I have included a picture that also shows M, the magnetization of a material along with H and B. M is like the polarization vector, P, of dielectric materials. If you need more info let me know but I'll leave you alone for now!
The light must be either very dim or else non-existent.
We can't see the light wave or the label.
<span>436 km
The conversion factor between kilocalorie/hour and watts is 1.163 (1 kcal/hr = 1.163 watt). So let's convert the energy consumption of the bird from watts to kcal/hr
3.7 w / 1.163 w hr/kcal = 3.18 kcal /hr
1 gram of fat has 9 kcal, so the total number of kcals consumed will be 4 * 9 = 36.
So the bird can fly for 36/3.18 = 11.32 hours
The distance traveled will be
11.32 h * 3600 s/h * 10.7 m/s / 1000 m/km = 436 km</span>
Answer:
The compression in the spring is 5.88 meters.
Explanation:
Given that,
Mass of the car, m = 39000 kg
Height of the car, h = 19 m
Spring constant of the spring, 
We need to find the compression in the spring in stopping the ore car. It can be done by balancing loss in gravitational potential energy and the increase in elastic energy. So,

x is the compression in spring

So, the compression in the spring is 5.88 meters.