Answer:
The star-sphere discovered by the Greeks and other ancient civilizations which shows the physical location in space of the nearby stars.
Explanation:
The celestial sphere is an ideal sphere, without defined radius, concentric with the terrestrial globe, in which the stars apparently move. Some ancient civilizations such as the Greeks assumed that the stars were attached to a celestial sphere, which revolves around the earth, while our planet is always immobile.
Answer:
The answer is letter B, absorb.
Explanation:
Heat travels through three different ways: radiation,conduction and convection.
Radiation- this happens when heat moves as energy waves (infrared waves) directly from its source to something.
Conduction- heat passes directly from one object to another through the touching of surfaces.
Convection- this occurs when warmer areas of a liquid or gas rise to cooler areas in the liquid or gas.
The transfer of heat in the situation above is an example of "thermal radiation." The campfire carries light energy through the fire. These consists of electromagnetic waves (most of these are infrared light). These waves (radiation) carry energy, which is then converted to heat once it hits another object that absorbs it. In the case above, once the hands absorbs the energy, it then warms up. This happened because the hands are placed <u><em>near the campfire.</em></u> Placing the hands near the campfire is important because air is a poor thermal conductor.
Thus, the answer above is letter B, absorb.
The question is missing, however, I guess the problem is asking for the value of the force acting between the two balls.
The Coulomb force between the two balls is:
where
is the Coulomb's constant,
is the intensity of the two charges, and
is the distance between them.
Substituting these numbers into the equation, we get
The force is repulsive, because the charges have same sign and so they repel each other.
