C) above, the Earth's core is about the melting point of iron.
1. C. Gravitational attraction exists between the two objects.
Explanation:
Gravitational attraction is always exerted between two objects which have mass, and its magnitude is given by:

where G is the gravitational constant, m1 and m2 the masses of the two objects, and r the separation between them. Since the two objects have for sure non-zero masses m1 and m2, even if they are 20 miles apart, the value of the gravitational attraction F is non-zero, so the correct answer is C.
2. D. Two atoms come together to form a molecule.
Explanation:
this outcome is actually caused by the electrostatic forces between the two atoms, not by gravitational force. In fact, gravitational force becomes relevant only when the masses of the two objects involved are large enough: this is the case for planets, stars, galaxies, and objects in the universe. However, two atoms have very small masses, so the gravitational force between them is really negligible. On this smaller scales, the electrostatic force is much stronger than the gravitational force, so the electrostatic force is the real responsible for the formation of bonds between atoms.
Answer:
23.52092 J
Explanation:
m = Mass of block = 6.79 kg
s = Sliding distance = 2.82 m
= Angle of slide = 20.7°
= Coefficient of kinetic friction = 0.425
g = Acceleration due to gravity = 9.8 m/s²
Work done by the force of gravity is given by

The work done by the force of gravity is 23.52092 J
Answer:
The correct option is;
How loud or soft the sound is
Explanation:
The loudness of a sound wave is given by the amount of energy that the pressure wave carries and it is measured in decibels (dB) which is the relative intensity of the pressure wave of a sound to the standard pressure
A loud sound has a high amplitude and a soft sound has a low amplitude, such that as the amplitude of the sound is increased, due to increased energy input, the sound becomes louder, and as the amplitude of the sound is decreased due to reduced energy input, the sound becomes softer.