Answer:
Solar and nuclear power generate more than 99 percent of our civilization's energy. Every other important source of energy is a combination of these two. The majority of them are solar in nature. We discharge previously collected solar energy when we burn wood.
and
Nuclear energy, fossil energy (oil, coal, and natural gas), and renewable energy (wind, solar, geothermal, and hydropower) are all examples of primary energy sources.
Explanation:
Answer:

Explanation:
The acceleration of an object is the rate of change of velocity of the object.
Mathematically, it is calculated as:

where
u is the initial velocity
v is the final velocity
t is the time taken for the velocity to change from u to v
Acceleration is a vector, so it is important to also take into account the direction of the velocity.
For the particle in this problem, we have:
u = +48 m/s is the initial velocity (positive direction)
v = -92 m/s is the final velocity (negative direction)
t = 4.5 s is the time interval
Therefore, the average acceleration is

The answer they are looking for is the last one. However the last two are technically correct but the third one would result in negative work.
Answer:
The frictional torque is 
Explanation:
From the question we are told that
The mass attached to one end the string is 
The mass attached to the other end of the string is 
The radius of the disk is 
At equilibrium the tension on the string due to the first mass is mathematically represented as

substituting values


At equilibrium the tension on the string due to the mass is mathematically represented as



The frictional torque that must be exerted is mathematically represented as

substituting values


Answer:
1: surface temperature
2: red giant
3: The brightest stars are called supergiants. Star clusters are rich in stars just off the main sequence called red giants. Main sequence stars are called dwarfs.
4: A white dwarf is very dense
5: red giant
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