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:
Answer:
When the bat hits the ball, it exerts some force on the ball. Just think about a home run hitter hitting a stationary ball. How far do you think it will go? Will it go more than 400 ft.? Probably not. While the kinetic energy transferred from the bat to the ball accounts for some energy of the ball, it does not account for all. Where is the mysterious energy coming from?
The answer is conservation of momentum. I just said momentum is conserved but how do I know that? I know that because of Newton's 2nd law: F=ma (Force equals mass times acceleration)
Conservation of momentum means that the harder you throw you, the harder the ball will bounce back at you. That is the reason it is easier to hit a home run on a fast ball than a curveball.
Conservation of momentum also means that the bat can transfer some of its momentum to the ball. This is why it is better to use a heavier bat if you swing just as fast. The momentum is the product of the mass and velocity, so to make it easier to understand;
a heavier bat swung at the same speed as a lighter bat will have more momentum.
The answer would be C since metals have electrons that help in heating up the metal
