Answer: Larmor suggested in 1919 that a self-exciting dynamo could explain the magnetic field of the earth, as well as that of the sun and other stars, but it was Elsasser and Bullard in the 1940s who showed how motion in the liquid core of the earth might produce a self-sustaining magnetic field. By this time seismology and other studies had given a clearer picture of the earth, as having a solid inner core, a liquid outer core, both with a composition more of metal (mainly iron) than rock, and a rocky mantle, all below a thin crust that is all we can directly see. Energy from radioactivity travels outwards as heat, producing thermal convection in the core. It seems that this convection is the cause of the earth's magnetic field, although our knowledge of the core and its dynamics is sketchy. Our knowledge is limited to saying that flow regimes like those that may be occurring in the core can produce self-sustaining dynamos, with characteristics similar to that needed to produce the earth’s magnetic field.
Explanation:
<span>A ball is thrown downward at 5ms from roof 10m high its velocity when it reaches the ground is 0 m/s. This is because it already dropped from the ground or x axis. So the velocity already stopped. </span>
Answer:
The answer is 3.33m
Explanation:
The acceleration "a" is constant.
Acceleration is the variation of velocity over time,
.
solving the last equation
,
where
because the airplane starts from rest.
Once again, velocity is the variation of distance over time.

then

where
if we consider the end of the runway as the initial point (this step is for simplicity but you can let it expressed, it's going to cancel anyway).
If
at
, then

and the final expression for the distance is
.
If t = 2s, x = 4.44 m. Which means thad the additional distance is

Answer:
F = 309.24 N
Explanation:
Given that,
Charge on a strom cloud, q₁ = 0.055 C
The charge gained by the top of a tree, q₂ = -0.006 C
The cloud moves to 98 meters above the tree.
We need to find the amount of force between the cloud and the tree. The electrical force between two charges is given by :

So, the force between the cloud and the tree is equal to 309.24 N.
Explanation:
They will repel, meaning that they are made of an electrical conductor.