Calcium has 2 valence electrons
Answer:
Black Hole
Explanation:
A black hole is a very dense and massive stellar object, which has a field of gravity so large that not even light can escape it.
Since it does not emit light, <u>we cannot see them directly</u>, hence the name of black hole.
So in this case,<u> if the object has a mass of 8 solar masses that is enough to form a black hole</u>, and <u>also cannot be seen</u>, all of this indicates that the object we are talking about is a black hole.
It should be mentioned that although these objects do not emit light, because it cannot escape due to the immense force of gravity, black holes can be detected by a type of radiation emitted on their event horizon due to quantum effects called Hawking radiation .
Answer:
A) some of the rocks energy is transformed to thermal energy
Explanation:
If we neglect air resistance during the fall of the rock, than the mechanical energy of the rock (which is sum of its potential energy and its kinetic energy) would be constant during the entire motion, so the total energy of the rock at the top would be the same as the sum of its potential energy and kinetic energy at the bottom.
However, this not occurs, due to the presence of air resistance. In fact, air resistance acts against the fall of the rock, and because of the friction between the molecules of air and the surface of the rock, the rock loses part of its energy. This energy is converted into thermal energy of the molecules of the air.
The answer is C. F=ma basically says that force is a function of mass multiplied by acceleration. The first two answers don’t make sense because there’s no necessary relationship between mass and acceleration. And for the last two, the higher the mass, the higher the force needed, therefore C is the correct answer.
